What Is the Best Time Step to Use to Download Daily Sunshine Duration From Ecmwf

General description

The processing of observed station atmospheric condition into the MCYFS involves four steps:

preprocessing of station weather data

Information acquisition from weather stations

Weather stations (black dots) for which data are bachelor for (part of) the menstruation from 1975 until present

The selection of stations is limited to those stations that regularly collect information and can supply data in virtually real fourth dimension. Relevant meta data of stations includes station number, station name, latitude, longitude and altitude. This data is available in the object STATIONS.

Currently, data conquering and processing applies to two regional windows: Europe and Communist china. Mainly examples from Europe are shown in this documentation.

Some of the celebrated meteorological data were purchased directly from National Meteorological Services. Others were acquired via the GTS. As data are obtained from a diverseness of different sources, considerable pre-processing was necessary to convert them into a standard format. Around 1992 the celebrated meteorological data represented approximately 380 stations in the EU, Switzerland, Poland and Slovenia with information from 1949 to 1991 (Burrill and Vossen, 1992). Subsequently the celebrated sets have been extended with stations in Eastern Europe, western Russia, Maghreb and Turkey. The historic data were converted into consequent units and checked on realistic values. The database was likewise scanned for inconsistencies, such every bit successive days with the same value for a variable, or minimum temperatures higher than maximum temperatures (Burrill and Vossen, 1992).

From 1991 to present, meteorological data is received in near-real-time from open information sources and from contracted providers like ECOMET or national or regional meteorological services. Sources include the WMO GTS network, NOAA information access points, regional and national meteorological services, and the admission points for non-essential WMO reports. The data arrives either in standardized encoded formats equally defined by the WMO or ICAO, or in proprietary formats equally used by individual providers. It is first decoded and converted into a generalized construction, including unit and time zone conversions, alignment of reference periods and - where needed - the assignment of station-id. Basic first level data sanity checks are applied. In a next pace, the information is converted into the input-format equally required by the [Software Tools#QUACKME|QUACKME]] software package. The temporal resolution of the information ranges from one-hourly to 24-hourly, depending on the parameter. QUACKME is applying data quality checks, calculates derived parameters and daily aggregates and writes the information into the file formats equally expected by the EFAS and MCYFS downstream processes.

In recent years, the earlier archives (1975-2004) of Scandinavia and eastern Europe have been enriched. In 2016 information from around 300 Chinese stations take been acquired starting a new service for this region.

Bachelor stations

The stations, stored in object STATIONS holds over 10221 stations distributed over twoscore countries in Europe and neighboring countries. Over 5100 of these stations provide weather condition data in near existent fourth dimension. All weather data is stored in the stations atmospheric condition database (daily information in object WEATHER_OBS_STATION and three- and 6-hourly precipitation in object WEATHER_OBS_STATION_RAIN).

Raw station data is nerveless from various sources:

• GTS (essential data and information licensed by ECOMET restrictions)
• NOAA (United states)
• European National Meteorological Institutes (NMI) (licensed)
• Diverse regional networks in Europe

For transmission and international exchange, the internationally exchanged station reports are encoded in formats standardized and maintained past WMO and International Civil Aviation Organizaton (ICAO)

• SYNOP (WMO-code FM12)
• BUFR (WMO-code FM94
• METAR

Observations as provided directly by National Meteorological Institutes or regional authorities come from secondary networks and are provided in proprietary formats.

Meteorological stations selected in priority are those located in the agricultural zones and equally distributed over the mainland (instead of over islands - for Portugal, Espana or Greece in particular). In detail, for western Russia (western of Urals) the main areas covered are the agricultural districts.

In the instance of China roughly 300 stations were selected meeting the post-obit criteria:

• Nigh real time delivery
• A xx-years archive
• Located in the main agricultural areas
• Covering the elements: precipitation, minimum and maximum temperature, humidity and wind speed

The raw station data for Red china is collected from GTS.

Basic indicators

The basic indicators that are received from weather stations include:

• Sum of precipitation
• 2m air temperature
• Maximum of 2m air temperature
• Minimum of 2m air temperature
• Downward directed solar radiation measured at globe'south surface (global radiation)
• Elapsing of sunshine
• Total cloud cover
• Water vapour force per unit area
• Relative humidity
• 10m mean wind speed
• Snow depth

For WMO SYNOP FM 12 and BUFR FM 94 bulletins, WMO defines regional regulations to consider fourth dimension zones and national coding practices. The extent of reported parameters and the report frequency differs per country and is for ECOMET fellow member countries affected as well by license restrictions.

The METAR code is standardized through the ICAO. In Europe and China, the WMO-maintained codes SYNOP FM12 and BUFR FM 94 provide college accurateness for the various parameters and more item. In these regions, METAR provides only temperature, dew point, visibility, cloud amount and wind speed and is reported in coarser increments for the various parameters. The reporting frequency is determined past the private flying operation of each aerodrome. Yet, METAR reports are used also, by and large to make full spatial gaps in areas with less WMO stations.

Observation data from several European regional meteorological networks became bachelor afterward 2015. The data from regional networks are generally not available in the standard meteorological formats, but take to be collected and converted individually. The quality of the data is adamant by the installed sensors and the siting of the stations. The reported parameters and frequency differ by network.

The post-obit table summarizes basic information on the availability and reporting regulations from the various observing station data sources:

Parameter	Reference periods of reports every bit defined past WMO	WMO formats BUFR or SYNOP (*)	METAR (**)	Regional networks
Sum of atmospheric precipitation	24-hourly sum, 12-hourly sums, half-dozen-hourly sum, ane-hourly sum reported, depending on region WMO-region and local regulations	Europe: 06 UTC: past 24 hours / 00 UTC and 12 UTC: past 6 hours / 06 UTC and 18 UTC: past 12 hours / 1-hourly -- China: Reports 00 UTC for past 24 hours, some stations report 21 UTC for previous 24 hours (***)	Not reported in Europe and Prc	Private, generally 1-hourly
2 m air temperature	Instantaneous value	Reported with 0.1 One thousand accuracy	Reported as full degrees	Generally 0.ane Thou accuracy
Maximum ii grand air temperature	Maximum of continuous measurement during reference period (****)	Europe and China: reported 18 UTC	Not reported in Europe and China	Individual
Minimum 2 thousand air temperature	Minimum of continuous measurement during reference period (****)	Europe and Prc: reported 06 UTC	Not reported in Europe and Prc	Individual
Downwards directed surface solar radiation (global radiation)	Sum accumulated over past 24 hours, sum past 1 hour	Bachelor for some European countries at 00 UTC, 1-hourly	Not reported in Europe and China	Individual definition, mostly ane-hourly
Duration of sunshine	Sum accumulated over past 24 hours	Most European countries written report at 06 UTC	Non reported in Europe and China	Individual, mostly one-hourly
Total deject cover	Instantaneous value	Octas 0-8	5 stages, only clouds up to a summit of 5000 feet over footing reported	Not reported
Measures for the humidity of the air at 2 m above footing: dew point, water vapour pressure level and relative humidity	Instantaneous value of dew signal temperature reported (*****)	Reported with 0.i K accuracy	Reported as full degrees	to be derived from other humidity parameters similar relative humidity and air temperature
x m mean wind speed	Mean over past x minutes	Meters per 2d	By and large full knots, occasionally less accurateness during low air current situations	Individual definition
Snow depth	Instantaneous value, increasing automatization of measurement	When a station reports snow depth, it is washed in Europe by 06 UTC, in People's republic of china by 00 UTC	not reported	Non reported

(*) Principal synoptic hours are 00, 06, 12, xviii UTC. Intermediate synoptic hours are 03, 09, 15, 21 UTC. For most European countries, ane-hourly information is used as well.
(**) The written report frequency is determined by the drome's schedule and tin can be as often equally 20 minutes. The frequency of reports tin can change over daytime, weekday, and season.
(***) In BUFR, several countries do not provide the reference flow during dry atmospheric condition in the FM94 lawmaking, supposedly by accident. In this case, it is assumed that the WMO definitions for the reference menses are applied.
(****) Europe: Covers past 12 hours. Cathay: Covers past 24 hours.
(*****) Other thermodynamical measures for the humidity of air tin can be calculated from dew signal and air temperature.

Data quality check

The software parcel Quality Checks Meteorological Information (QUACKME)equally developed by the JRC is the chief processing tool for completing and quality evaluation of actual meteorological data which is used equally input for agro-meteorological models. The data processing workflow with quality command and aggregation can exist described equally follows.

Near real-time pre-processing (1-hourly reports with extended data at intermediate and main synoptic hours, irregular reports)

• Near real-time collection of reports from the diverse information sources.
• Decoding of the WMO and ICAO standard formats with dedicated decoder software (FMDecode). Reports in other formats from regional, secondary networks are translated into a uniform construction using individual proprietary converters.
• The data is converted into a generalized structure, including the conversion towards UTC, standard units, the alignment of reference periods and the calculation of derived parameters. Basic sanity checks are practical.

Training of QUACKME input data

• Generate a csv with all bachelor ascertainment information for the period of 24 hours (07 UTC - 06 UTC next twenty-four hours) for the European region and for China, respectively. The format of the csv is described in the QUACKME Technical Guide.
• When data from a station are institute to be erroneous for a longer time, the station can be listed on a and so-chosen blacklist, either past parameter or for the whole report. Observations from blacklisted station-parameter combinations are not written into the csv. The blacklist is manually checked every iii months.If the messages are considered trustworthy again, the station-parameter combination is removed from the blacklist.
• Generate csv with location specific, near existent time forecasts for the same stations and period equally the data in the observation-csv. The format of this csv is as well described in the QUACKME Technical Guide.

For a number of weather elements, QUACKME compares the observed values with almost-real-fourth dimension forecast values. The forecast is used equally reference for the reasonable range of possible values. The forecasts are obtained through a technique chosen MOS (Model Output Statistics). Meteorological forecast models, east.g. the ECMWF model, compute the physical condition of the atmosphere on a grid, and the results correspond the expected situation per filigree box. The MOS forecast is using statistical relationships between the observations of a particular station and historic model forecasts for surrounding grid points. Each observing location has its own statistics. In this way, the local conditions at the weather condition station can be modelled much more than accurately. QUACKME is using the individual location forecasts to ascertain time- and location-dependent thresholds for the trustworthiness of station reports, for the elements air temperature (including minimum and maximum), dew point (applies to all derived measures for the humidity of the air), atmospheric precipitation, and current of air speed, respectively. That way, the thresholds consider season, climatology and even the actual weather pattern. A welcome side effect is the high spatial consistency of the statistical MOS approach and therefore of the thresholds. Individual MOS forecasts is used for almost all stations (approx. 5000, land Jan 2021).

Running the QUACKME modules and interactive data quality checks past the meteorologist

• This does not apply for precipitation, i.e. for consecutive reports of 0 mm. This rather typical reporting bug is not found when quality checks are applied on to the data of the very 24-hour interval. Due to the mostly "patchy" pattern of atmospheric precipitation events quality checks accept dry stations in between. To find stations that report consecutively 0 mm several weeks of history demand to be considered, come across retrospective checks.
• Correct automatically obvious errors detected while performing these checks;
• Automatically fill gaps in the database through interpolation based on time consistency criteria;
• Flag dubious observations which cannot be corrected automatically;
• Write all automatic corrections and flagged dubious observations to a log file;
• Take the flagged observations checked and, if necessary, corrected by a trained meteorologist; when a correction is done, the derived parameters are recalculated and the data are written dorsum to the database.

Defended trained and qualified meteorologists go through the dubious ascertainment values that are flagged as such by the QUACKME automatic pre-checking program. An interactive arrangement for the visualization of meteorological data is used to graphically visualize and clarify additional information such as:

• Station observation data
• Satellite images
• Precipitation Radar data
• Assay and brusque range forecasts computed by physical models of the temper
• Brusk range forecasts for weather station locations

This additional data is used by the analyst to decide on either confirmation or rejection of the observed values.

Conversion to daily values

One time the database has been filled following the method described to a higher place, information are aggregated to daily values. This includes the indicators equally summarized in the post-obit table:

Parameter	Assemblage	Reference menstruation Europe	Reference flow China
Full cloud cover (N)	Daily mean	00 UTC, 03 UTC, 06 UTC, 09 UTC, 12 UTC, 15 UTC, 18 UTC, 21 UTC, 00 UTC side by side twenty-four hour period	xviii UTC prev., 21 UTC prev., 00 UTC, 03 UTC, 06 UTC, 09 UTC, 12 UTC, 15 UTC, 18 UTC
Duration of sunshine (Msun)	24-hourly sum	00–24 UTC	Not available
Down directed surface solar radiations (global radiations) (Mrad)	24-hourly sum	00-24 UTC	Not available
Minimum 2m air temperature (Tn)	Lowest value of continuous reference period (*)	18 previous day -06 UTC	06 UTC previous day – 06 UTC
Maximum 2m air temperature (Tx)	Highest value of continuous reference period (**)	06-18 UTC	xviii UTC previous mean solar day – 18 UTC
Water vapour pressure (east)	Daily hateful	00 UTC, 03 UTC, 06 UTC, 09 UTC, 12 UTC, 15 UTC, eighteen UTC, 21 UTC, 00 UTC next mean solar day	xviii UTC prev., 21 UTC prev., 00 UTC, 03 UTC, 06 UTC, 09 UTC, 12 UTC, fifteen UTC, 18 UTC
10m mean current of air speed (ff10)	Daily mean	00 UTC, 03 UTC, 06 UTC, 09 UTC, 12 UTC, 15 UTC, 18 UTC, 21 UTC, 00 UTC adjacent day	xviii UTC prev., 21 UTC prev., 00 UTC, 03 UTC, 06 UTC, 09 UTC, 12 UTC, 15 UTC, 18 UTC
Sum of atmospheric precipitation (RRR)	24-hourly sum	Mostly 06 UTC until 06 UTC adjacent morning	More often than not 00 UTC – 00 UTC next day (indicator two). For some stations 21 UTC previous day – 21 UTC (indicator six)
2m air temperature (TT)	03-hourly instantaneous values during daytime	06 UTC, 09 UTC, 12 UTC, xv UTC, eighteen UTC	00 UTC, 03 UTC, 06 UTC, 09 UTC, 12 UTC
Relative humidity (RH)	03-hourly instantaneous values during daytime	06 UTC, 09 UTC, 12 UTC, 15 UTC, xviii UTC	00 UTC, 03 UTC, 06 UTC, 09 UTC, 12 UTC
Land of soil	Instantaneous value (***)	00 UTC following solar day
Water vapour pressure deficit (vpd)	Daily hateful	00 UTC, 03 UTC, 06 UTC, 09 UTC, 12 UTC, xv UTC, 18 UTC, 21 UTC, 00 UTC next day	18 UTC prev., 21 UTC prev., 00 UTC, 03 UTC, 06 UTC, 09 UTC, 12 UTC, 15 UTC, 18 UTC
Slope of saturation vapour force per unit area vs. temperature curve slope	Daily mean	00 UTC, 03 UTC, 06 UTC, 09 UTC, 12 UTC, 15 UTC, 18 UTC, 21 UTC, 00 UTC next day	18 UTC prev., 21 UTC prev., 00 UTC, 03 UTC, 06 UTC, 09 UTC, 12 UTC, 15 UTC, xviii UTC
Total cloud comprehend (N)	Daytime mean	06 UTC, 09 UTC, 12 UTC, 15 UTC, eighteen UTC	00 UTC, 03 UTC, 06 UTC, 09 UTC, 12 UTC
Low or (when no low clouds) medium clouds (Nh)	Daytime hateful	06 UTC, 09 UTC, 12 UTC, fifteen UTC, xviii UTC	Not available
Calculated sunshine elapsing (Csun)	24-hourly sum	To exist calculated by QUACKME, 0-24 UTC of the mean solar day specified	To be calculated by QUACKME, eighteen UTC previous day - 18 UTC of the twenty-four hour period specified
Highest possible global radiations at clear sky (Crad)	24-hourly sum	To be calculated by QUACKME, 0-24 UTC of the mean solar day specified	To be calculated past QUACKME, 18 UTC previous day - 18 UTC of the day specified
Potential evapotranspiration (ETP)	24-hourly sum	To be calculated by QUACKME, 0-24 UTC of the day specified	To exist calculated by QUACKME, 18 UTC previous day - xviii UTC of the mean solar day specified
Visibility (VV)	Daytime hateful	06 UTC, 09 UTC, 12 UTC, 15 UTC, 18 UTC	00 UTC, 03 UTC, 06 UTC, 09 UTC, 12 UTC
Snow depth	Instantaneous value	06 UTC	00 UTC

(*)When no minimum is reported merely hourly instantaneous temperatures QUACKME estimates the minimum from the hourly local early morn values, see QUACKME documentation.
(**)When no maximum is reported but hourly instantaneous temperatures QUACKME estimates the maximum from the hourly local afternoon values, encounter QUACKME documentation.
(***)Code, for translation see BUFR documentation.

Information on the fashion the daily element values are constructed/defined is stored in the object WEATHER_OBS_STATION_INFO. Currently this is but done for precipitation east.g. menstruum definition of the daily rainfall sum. Codes are:

• 0 = real observation 06 - 06 UTC side by side solar day
• 1 = menses 06 - 06 UTC adjacent day, short range forecast has been used to encompass the complete menstruation
• two = real observation 00 UTC - 24 UTC
• 3 = real observation 03 UTC - 03 UTC next day
• 4 = real ascertainment 12 UTC previous twenty-four hour period - 12 UTC
• 5 = real observation eighteen UTC previous day - 18 UTC
• 6 = real observation 21 UTC previous day - 21 UTC

More information on the iii- and 6-hourly precipitation data are stored in object WEATHER_OBS_STATION_RAIN (column IDFLAG). Codes are:

• 1 = Inverse by meteorologist (not applicable)
• ii = Automaticaly corrected (not applicative)
• iii = Observation
• iv = Linear interpolation from observations
• 5 = Interpolated via MOS from observations
• 6 = MOS analyses (not managed still)

Finally, meta data of all stations is checked once a year.

Retrospective checks and blacklisting of suspect stations

Some suspicious station reports are only detectable by checking time series of several weeks. Continuous reports of 0 mm atmospheric precipitation (instead of a "precipitation not observed" flag) exercise not stick out in daily rainfall sums, just simply past investigating the station's reports over a longer period. Global radiation and cloud embrace have a high spatial volatility, and continuous observation or encoding errors at a certain station become more explicit when looking into several weeks of station reports.

For all European stations, the QUACKME output of the past 40 days is inspected each week through time series checks. Provided a station reported on more than one-half of the tested days, the reports are checked, consulting ECMWF model analysis and brusque range forecasts for model filigree points surrounding the station of request.

The checks are set up equally follows:

Atmospheric precipitation

A station is flagged as suspicious for precipitation when suspicious sequent zero rainfall reports are detection. Criteria are

• The observed precipitation sum is 0 mm whan aggregated over the whole checked flow.

AND

• the ECMWF model near real time forecasts during the checked period included at least ten wet days. A day is considered existence moisture when more than 0.5 mm precipitation is forecasted by the model'south near real time foreast.

Radiation

For each twenty-four hour period of the investigated menstruum, the station's maximum possible daily solar radiation sum is calculated, based on its latitude, the fourth dimension of yr, and using a standard atmospheric optical depth. A station is flagged as being suspicious for radiations when:

• In that location are at least 10 days with observed solar radiation exceeding 110 % of the maximum possible corporeality of solar radiation.

OR

• There are at least 10 days on which the observed solar radiations remained below 10 % of the maximum possible daily sum of solar radiation.

OR

• There are at least 10 days with observed radiations of 0 MJ m-two day-i whilst the ECMWF short-range forecast analysed solar radiations exceeding 0 MJ m-2 day-i.

OR

• The total sum of observed solar radiation is less than 25 % of the maximum possible radiation sum for the menstruation, whilst the sum of the model's short-range forecasts for the parameter exceeded 25 % of the maximum possible daily sum of solar radiation. Naturally, the maximum possible radiation catamenia's is only summed up from days with observations being bachelor.

Mean daytime cloudiness

A station is flagged every bit being suspicious for cloudiness when:

• A difference of more than two.5 octa between the daily mean of observed total cloud embrace and the daily mean of ECMWF model analysis and short-range forecast for full deject is constitute for all days of the investigated catamenia.

OR

• The reported instantaneous cloudiness was ever higher than 4.0 octa whilst the model analysis and short-range forecasted for at to the lowest degree three time steps (hours) in the period a total cloud cover of less then 3.0 octa.

OR

• For all time steps in the menses more five octa full cloud cover was reported.

Duration of sunshine

For each day in the investigated period, the maximum day length is calculated based on the day of the year and the station latitude. Dividing the observed sunshine duration for a twenty-four hours past the calculated day length gives the relative sunshine.
A station is flagged equally being suspicious for sunshine duration when:

• For more than 10 days in the menses, the observed elapsing of sunshine is more than than 110% of the calculated day length.

OR Depending on the dominant season during the menstruation:

• Summer: highest relative sunshine value is less than 30% (i.eastward. the station is always cloudy).
• Winter: the lowest relative sunshine value is more than than 70% (i.due east. the station is ever sunny)
• Spring/fall: highest relative sunshine value is less than 30% (see summer bank check) OR the lowest relative sunshine value is more than than 70% (encounter winter check).

The dominant season is determined equally the flavour with the largest number of days in the investigated period. When 50% of the investigated days are winter/summer days, the dominant flavor will be winter/summer.

When the process flags stations equally suspect a final manual inspection by a meteorologist follows. If the time series of the station are constitute to exist wrong the following actions are executed:

• The station is added to a blacklist: the station is immediately excluded from the operational station list.
• The erroneous time series are deleted from the objects WEATHER_OBS_STATION_RAIN and WEATHER_OBS_STATION. The erroneous values are flagged (object WEATHER_OBS_STATION_RAIN, cavalcade Type) or deleted (object WEATHER_OBS_STATION and WEATHER_OBS_STATION_INFO) and deleted values are saved in separate objects (WEATHER_OBS_STATION_ERRORS and WEATHER_OBS_STATION_INFO_ERR).
• All affected grid cells (object WEATHER_OBS_GRID) and regions (object WEATHER_OBS_REGIONCOVER) are reprocessed at regular time intervals. This likewise includes the ingather simulation results.

Every iii months, by the end of the quarter, each station on the blacklist is verified. Afterwards information technology is decided if stations can return to the operational work flow. Falsely blocked information is dorsum-ordered, added and reprocessed.

Station data availability

Each month an overview is created showing the delivered number of stations per country. Information is also added on sudden changes and follow-up actions. Example monthly overview

Every day, the newly produced information files are compared with those of the previous day. If the number of delivered values for private countries and parameters decreases significantly, an alert is sent by email is sent to the project team. The threshold in a higher place which a reject in the number of values delivered is considered critical depends exponentially on the number of values in the state.

The number of values flagged past the weak, heavy and threshold checks of QUACKME are monitored on a daily and on a monthly ground. Stations that are flagged particularly frequently are identified and the cause tin can be analysed separately. As a result, stations tin can be blacklisted or an comeback of the QUACKME checks can exist suggested.

The following maps illustrate the available stations (red 0-20% - green eighty-100%) for the chief elements in a contempo year 2019. The main elements (maximum temperature, minimum temperature, precipitation, lord's day shine, cloud cover, wind speed and vapor pressure level) take a practiced spatial spread over Europe with a relative loftier spatial density in western and cardinal Europe. Availability of measured radiations is mainly limited to western and central Europe.

maximum temperature	minimum temperature	atmospheric precipitation
global radiations	sunshine	cloud cover
wind speed 10m	vapor pressure	snow depth

The following graph shows the increase of observations for the main elements betwixt 1975 and 2019. Most elements have at least 600,000 annual observations which equals over more than 1600 stations in case they would have a consummate temporal coverage. However, nearly stations have temporal gaps and therefore the number of reporting stations is much higher. Since 2004 the number of observations increased up-till a level of effectually i,500,000 reported past more than 4500 stations. During the recent years also observations of radiations related elements increased drastically. This is especially truthful for cloud encompass and sunshine. Prior to 1995 these elements accept a relative low number of observations significant that the global radiation of these years, required in MCYFS, is mainly based on the daily temperature range, run into Calculation of avant-garde parameters.

In full general the station density and available data in the monitored areas is considered sufficiently high for the purpose of the projection.

Ingestion into the database

Afterward the station weather data passed all checks, daily atmospheric condition data is exported to a fixed formatted ASCII file (south-file) containing the information of a single day that can be imported in the object WEATHER_OBS_STATION. In the near existent time state of affairs a s-file is delivered one day later. For example in the afternoon of day 31 March 2016 the following file is generated: s20160330.dat.

Format ASCII s*.dat file (daily station weather)

ELEMENT POSITION TEXT FILE Clarification UNIT AGGREGATION_PERIOD/REFERENCE Menses STATION_NUMBER position(01:07) station number - - DAY position(08:17) date as YYYYmmdd - - CLOUD_24_TOTAL position(eighteen:23) daily hateful of total deject embrace octas mean over 24 hours, run into Conversion to daily values SUNSHINE position(24:29) sunshine duration h sum of 24 hours, run across Conversion to daily values RAD_MEA position(30:35) measured global radiation MJ one thousand-2 twenty-four hour period-i sum of 24 hours, see Conversion to daily values TEMP_MIN position(36:41) minimum temperature 0C minimum of 12 hours in Europe, 24 hours in China, see Conversion to daily values TEMP_MAX position(42:47) maximum temperature 0C maxiumum of 12 hours in Europe, 24 hours in People's republic of china, see Conversion to daily values VAP_PRES position(48:53) daily mean vapour pressure level hPa mean over 24 hours, run into Conversion to daily values WIND_10 position(54:59) daily mean air current speed at x metres m.s-1 hateful over 24 hours, see Conversion to daily values Rain position(sixty:65) corporeality of precipitation mm.d-i sum over 24 hours, come across Conversion to daily values TEMP_06 position(66:71) air temperature morning degC 06 UTC in Europe, 00 UTC in China HUM_06 position(72:77) relative humidity morning % 06 UTC in Europe, 00 UTC in China TEMP_09 position(78:83) air temperature late morning degC 09 UTC in Europe, 03 UTC in Cathay HUM_09 position(84:89) relative humidity late morning % 09 UTC in Europe, 03 UTC in People's republic of china TEMP_12 position(ninety:95) air temperature midday degC 12 UTC in Europe, 06 UTC in Communist china HUM_12 position(96:101) relative humidity midday % 12 UTC in Europe, 06 UTC in China TEMP_15 position(102:107) air temperature afternoon degC fifteen UTC in Europe, 09 UTC in China HUM_15 position(108:113) relative humidity afternoon % 15 UTC in Europe, 09 UTC in Communist china TEMP_18 position(114:119) air temperature evening degC xviii UTC in Europe, 12 UTC in Cathay HUM_18 position(120:125) relative humidity evening % eighteen UTC in Europe, 12 UTC in China STATE_SOIL position(126:131) state of the soil lawmaking* instanteneous value, see Conversion to daily values VAP_PRES_Def position(132:137) daily mean vapour pressure arrears hPa mean over 24 hours, see Conversion to daily values SLOPE_VP_VS_T position(138:143) daily mean slope saturation vapour pressure level vs. temperature bend hPa/°C mean over 24 hours, run across Conversion to daily values CLOUD_DAYTIME_TOTAL position(144:149) daytime mean of total cloud comprehend octas mean over 24 hours, run across Conversion to daily values CLOUD_DAYTIME_LOW position(150:155) daytime mean corporeality of CL clouds or, if no CL clouds are present, the daytime mean corporeality of CM clouds octas mean over daytime hours, encounter Conversion to daily values CLOUD_SHADOW position(156:161) daytime mean amount of shadow clouds octas mean over daytime hours no name** position(162:167) Calculated sunshine duration Csun % sum over 24 hours, see Conversion to daily values no name** position(168:173) Highest possible global radiation at clear sky Crad MJ k-2 day-1 sum over 24 hours, see Conversion to daily values no name** position(174:179) Potential evapotranspiration ETP mm/day sum over 24 hours, see Conversion to daily values VISIBILITY position(180:185) daytime mean visibility kilometres daytime mean, run into Conversion to daily values SNOW_DEPTH position(186:191) snowfall depth cm instanteneous value, run across Conversion to daily values RAIN_MOS position(192:197) indicator for reference period and usage of short range forecast in daily sum of precipitation RAIN - 0 = real ascertainment 06 - 06 UTC side by side day, one = menses 06 - 06 UTC adjacent day, curt range forecast has been used to embrace the complete catamenia, 2 = real observation 00 UTC - 24 UTC, three = real ascertainment 03 UTC - 03 UTC next twenty-four hours, 4 = real ascertainment 12 UTC previous twenty-four hour period - 12 UTC, 5 = real observation eighteen UTC previous day - 18 UTC, six = real observation 21 UTC previous day - 21 UTC) * Codes for state of soil: 0 = surface of ground dry out, without cracks or appreciable corporeality of dust or loose sand, 1 = surface of basis moist iii = flooded, 4 = frozen, 5 = coat on ground, 6 = loose dry grit or sand non roofing the ground completely, seven = thin cover of loose dry dust or sand roofing the footing completely, 8 = moderate or thick embrace of loose dry dust or sand roofing the basis completely, 9 = extremely dry with cracks. All codes refer to a surface of ground without snow or measurable ice cover. ** Non imported into the MCYFS database

The iii-hourly rainfall data is exported to a patently ASCII file (rrr3h_*.txt file) containing the data of 1 three-hourly fourth dimension step within i single twenty-four hour period. This data can be imported in the object WEATHER_OBS_STATION_RAIN. In the most real time service each day 8 rrr3h_*.txt files are generated at once containing information of eight iii-hourly fourth dimension steps:

• 09 UTC (06-09 UTC of previous day)
• 12 UTC (09-12 UTC of previous mean solar day)
• 15 UTC (12-xv UTC of previous day)
• eighteen UTC (15-18 UTC of previous day)
• 21 UTC (18-21 UTC of previous day)
• 00 UTC (21-00 UTC of previous twenty-four hour period)
• 03 UTC (00-03 UTC of nowadays day)
• 06 UTC (03-06 UTC of present 24-hour interval)

For instance in the afternoon of day 31 March 2016 the following files are generated: rrr3h_2016033009.txt, rrr3h_2016033012.txt, rrr3h_2016033015.txt, rrr3h_2016033018.txt, rrr3h_2016033021.txt, rrr3h_2016033100.txt, rrr3h_2016033103.txt and rrr3h_2016033106.txt.

Format ASCII rrr3h_*.txt file (3-hourly station rainfall)
Column header WMO number Date / time (UTC) Precipitation (mm/3h) Flag (1=Inverse by meteorologist/2=Automatically corrected/3=Observation/4=Linear interpolation from observations/5=Interpolated via MOS from observations/6=MOS analyses)

The half-dozen-hourly rainfall data is exported to a plain ASCII file (rrr_*.txt file) containing the information of one half-dozen-hourly time stride within 1 single day. This data can exist imported in the object WEATHER_OBS_STATION_RAIN. In the near real fourth dimension service each day 4 rrr_*.txt files are generated at in one case containing information of 4 half-dozen-hourly fourth dimension steps:

• 12 UTC (06-12 UTC of previous day)
• 18 UTC (12-18 UTC of previous day)
• 00 UTC (18-00 UTC of previous twenty-four hours)
• 06 UTC (00-06 UTC of present twenty-four hours)

For example in the afternoon of day 31 March 2016 the post-obit files are generated: rrr_2016033012.txt, rrr_2016033018.txt, rrr_2016033100.txt and rrr_2016033106.txt.

Format ASCII rrr_*.txt file (6-hourly station rainfall)
Cavalcade header WMO number Date / fourth dimension (UTC) Precipitation (mm/6h) Flag (i=Changed by meteorologist/two=Automatically corrected/3=Observation/iv=Linear interpolation from observations/5=Interpolated via MOS from observations/6=MOS analyses)

Adding of avant-garde parameters

Global radiation

Global radiations is the daily sum of incoming solar radiation that reaches the earth surface. It is mainly composed of wavelengths between 0.3 μm and 3 μm. Approximately half of the incoming radiations with wavelengths between 0.iv and 0.7 μm is Photosynthetically Active Radiation (PAR). Global radiation is the driving variable in the growth-determining CO2 assimilation procedure and thus crop growth models are sensitive to radiation data (van Diepen, 1992).

A major problem is the scarcity of measured global radiations. In cases where no directly observations are bachelor it must be derived from sunshine duration, cloud cover and/or temperature, on the basis of statistical relationships. If measured global radiation is missing, it is based on ane of three formulae (Ångström-Prescott, Supit-Van Kappel, and Hargreaves), depending on the availability of meteorological parameters. An of import component in these formulae is the corporeality of Angot radiation which is the extraterrestrial radiations integrated over the day at sure latitude on a certain day. The calculation of the Angot radiation and the three different formulae are described by Supit et al. (1994) and van der Goot (1998a).

Angot radiation

The principle component of all iii formulae is the extraterrestrial radiations, or Angot radiation. In fact, all of the 3 formulae estimate the fraction of Angot radiation really received at the earth surface. The Angot radiations is calculated every bit:

where: Ra  : Daily extra-terrestrial radiation, Angot radiation [J*1000-2*d-ane] Sc,d  : Solar abiding at the top of the atmosphere for a certain 24-hour interval [J*m-2*s-1] ∫sinβ dth : integral of solar peak over the day [south] The solar constant at the top of the atmosphere is calculated as: where: Sc,d : Solar constant at the peak of the temper for a certain day [J*chiliad-2*s-ane] Sc  : Average solar radiation at the top of atmosphere [J*m-two*s-ane] (1370 J*1000-ii*due south-1; I.Due east.A., 1978) td  : number of day (January 1 equal to 1) [-] The integral of the solar height over the solar day is a part of both the breadth of the position being considered also as the day of the year. The solar declination angle is a function of the twenty-four hour period of the year, and is calculated as follows: Where: δ : Solar declination [radians] td  : number of solar day (Jan one equal to 1) [-] For a given latitude, the necessary calculations now business concern the calculation of the astronomical twenty-four hours length, and the integral of the solar acme. The astronomical twenty-four hours-length is calculated every bit follows: where: D  : day-length [h] sinLD : sin(δ) * sin(latitude* π/180) [-] cosLD : cos(δ) * cos(latitude* π/180) [-] The integral of the solar height over the mean solar day can exist calculated as: Where: ∫sinβ dth : integral of solar height over the 24-hour interval [s] D  : daylength [h] sinLD  : sin(δ) * sin(breadth* π/180) [-] cosLD  : cos(δ) * cos(latitude* π/180) [-] For very high latitudes (>67°N), for a sure number of days per year, the day length tin exist 24 hours. In this case the to a higher place formulae no longer utilize. The programme checks for the value of sinLD/cosLD, and in case this value exceeds 1.0, the day length is set to 24 hours and the integral set to 24*3600 seconds.

The following hierarchical method is used to summate global radiation for each station (Supit and van Kappel, 1998) in case measured global radiation is missing:

Ångström-Prescott formula

If sunshine duration is available, global radiation is calculated using the equation postulated by Ångström (1924) and modified by Prescott (1940). The two constants in this equation depend on the geographic location.

where: Rg : global radiations [ J m-2 d-1] Ra : Angot radiations [ J m-2 d-1] n : bright sunshine hours per day [h] 50 : astronomical twenty-four hour period length [h] Aa, Ba : regression coefficients (Ångström-Prescott) [-]

Supit-Van Kappel formula

When neither measured radiations nor sunshine duration are available, only minimum and maximum temperature and daytime cloud cover are known, the Supit-Van Kappel formula is used. This is an extension of the Hargreaves formula (Supit, 1994). The regression coefficients depend on the geographic location.

where: Tmin, Tmax : minimum and maximum daily temperature [°C] CC : cloud comprehend in octets [-] As, Bs : regression coefficients (Supit) [-] Cs : regression coefficient (Supit-Van Kappel) [J g-two d-1]

Hargreaves formula

When only the minimum and maximum temperatures are known the equation of Hargreaves et al. (1985) is used. The regression coefficients depend on the geographic location.

where: Ah : regression coefficient (Hargreaves) [-] Bh : regression coefficient (Hargreaves) [J m-two d-1]

Whatever 1 of the to a higher place three methods has an additional upper limit. The maximum calculated global radiation is set to Angot radiation, corrected for atmospheric transmissivity, by multiplying the Angot value with the sum of the Angstrom A and B coefficients.

Deriving Ångström-Prescott, Supit-Van Kappel, and Hargreaves regression constants

The principal trouble with the application of the Ångström-Prescott, Supit-Van Kappel, and Hargreaves formulae is the quality of the regression constants. Studies by Supit (1994), Supit and van Kappel (1998) and van Kappel and Supit (1998) showed no relationship between latitude and the coefficients for Europe, although such a relation is frequently used to estimate these regression constants. Initially in MCYFS regression constants of Supit and van Kappel (1998) and van Kappel and Supit (1998) for Europe were used. They obtained sets of regression constants for the formulae for as many weather condition stations as possible, with a geographic distribution that corresponds to the area of interest for the MCYFS. As a result, a set of 256 reference stations was identified for which a relevant set of measured radiations data and other parameters in the formulae existed. For these stations regression constants were calculated based on measured radiations information for the iii formulae mentioned higher up.

In 2012 the regression coefficients of these solar radiation models for Europe were updated using a new set of conditions station data (temperature, sunshine and cloudcover) and an alternative training data set: 6 years (2005-2010) of the down-welling surface shortwave radiations flux (DSSF) 30-minutes product derived from Meteosat Second Generation satellite information by the Country Surface Analysis Satellite Applications Facility (LSA SAF) (Bojanowski et al.,2013). For each solar radiations model a set of conditions stations was selected having sufficient observations of either sunshine duration, or cloud embrace/temperature or but temperature (minimum and maximum) to perform a regression analysis. Results are stored in object STATION_REFERENCE_COEFFICIENTS (CGMS14SYS).

Station archive data for China did not include measured radiation nor sunshine. Therefore radiation was derived from other observed elements namely cloud cover and minimum and maximum temperature. The Hargreaves and Supit-VanKappel models have been trained using modelled radiation by Tang et al., 2013. The 50yrRad database of Tang et al., 2013 containing 'modelled' radiation data for 716 CMA stations, has demonstrated its superior operation over previous estimates of locally calibrated Angstrom-Prescott models. While radiation is based on the Hargreaves or Supit-VanKappel models, coefficients of the Angstrom method are still required to calculate net approachable long wave radiation inside the potential evapotranspiration calculation. For determining Angstrom coefficients only the 50yrRad archive was used. Since no sunshine duration data is bachelor, an alternative was sought. Transmissivity was derived past dividing the measured solar radiation at the ground past the solar radiation at the elevation of the atmosphere. By selecting only the period between twenty-four hours of year 150 and 200 (during mid-summer) the transmissivity is virtually constant and tin exist linked to the Angstrom coefficients.

The programme SupitConstants uses this gear up of data (via the view SUPIT_REFERENCE_STATIONS, CGMS14SYS), consisting of breadth, longitude, altitude and calculated regression constants, to derive the regression constants for all stations in the MCYFS. Interpolation of the regression constants of the reference stations to other stations is based on a distance weighted boilerplate of the iii nearest stations. This process is carried out in one case, unless the set of reference stations changes or when new stations are added or when meta data of stations change.

Interpolation of regression constants

Information of the reference stations, consisting of latitude, longitude, distance and the regression constants, is being used for the derivation of the regression constants for the prepare of stations used for the interpolation of the daily meteorological data. This is a procedure that merely has to be carried out in one case, unless the set of reference stations changes or when new stations are added or when meta information of stations change. Once the regression constants take been established for the operational set of stations, the global radiation estimation can proceed using any one of the formulae. The interpolation of the regression constants is based on a simple distance weighted boilerplate of the three nearest stations. For each of the three sets of constants (Ångström-Prescott, Supit-Van Kappel, and Hargreaves) a subset is created from the complete set of reference stations, by selecting but those stations that have the regression coefficients for the desired method. This subset of stations is then sorted based on distance to the station for which the regression coefficients are being calculated. This sorting procedure is also subject to an distance threshold test i.e. if the altitude difference betwixt the target station and a reference station is greater than a set threshold the reference station is rejected in favour of the next nearest reference station. Depending on a altitude threshold, the nearest one, two or three stations are then used to calculate the regression constants. If the threshold tests exclude all stations, the nearest station will be used, regardless of the distance. The altitude threshold value is 200 m; the altitude threshold is 200 km. The distance weighted average method used, is based on the relative altitude of the reference stations to the station of interest. Assume the distances d0, d1 and d2 to be the distances to the iii nearest reference stations, and w0, w1 and w2 the weights to be used in the calculation. Every bit an example, presume that d1 is 2*d0, then w1 will be w0/two. More than full general, w1 = w0*d0/d1. Similarly, w2 = w0*d0/d2. Furthermore, the sum of the weights should be ane, so w0+w1+w2 = 1. From the higher up, the post-obit relation can be established: w0 equals d1d2 / (d0d1 + d0d2 + d1d2) w1 equals d0d2 / (d0d1 + d0d2 + d1d2) w2 equals d0d1 / (d0d1 + d0d2 + d1d2)

Interpolated regression constants are written in the temporary object SUPIT_CONSTANTS (CGMS14SYS) and copied to object STATIONS (CGMS14SYS). Afterward the regression constants have been established for all stations, global radiations can be calculated past using whatever one of the above formulae. Finally, the derived daily global radiation of each station is written into object WEATHER_OBS_STATION_CALCULATED (encounter flowchart).

Evapotranspiration

Daily meteorological station data collected from stations does not contain potential evapotranspiration past crop, moisture soils and open up h2o. Potential crop evapotranspiration (ET0) is calculated by the Penman-Monteith equation while potential evapotranspiration of wet soils (ES0) and open water (E0) is calculated by the Penman equation.

Calculation of potential evapotranspiration

++ Penman-Monteith ++ Daily meteorological station data collected from stations does not contain potential crop evapotranspiration. This parameter is calculated by the Penman-Monteith equation (Allen et all., 1998). In general, the evapotranspiration from a reference surface, the and so-called reference crop evapotranspiration or reference evapotranspiration can be described past the FAO‑Penman-Monteith: where: ETo  : reference evapotranspiration [mm*day-1] Rn  : net radiations at the crop surface [MJ*m-ii* day-1] G  : soil oestrus flux density [MJ* m-2*twenty-four hours-1] T  : mean daily air temperature at 2 k pinnacle [°C] u2  : wind speed at ii m height [m*southward-ane] es  : saturation vapor pressure [kPa] ea  : bodily vapor pressure [kPa] es-ea : saturation vapor force per unit area deficit [kPa] Δ  : slope vapor pressure level curve [kPa* °C-i] γ  : psychrometric constant [kPa*°C-1] Commencement, some preprocessing is washed: Vapour presure is converted from hPa to kPa Incoming shortwave radiation (Rs) is converted from kJ.m-2.d-one to MJ.m-2.d-1 Windspeed is converted from 10 m to 2 one thousand: where: u2  : wind speed at two chiliad above ground surface [1000 south-1] uz  : measured wind speed at z m above ground surface [k s-i] z  : tiptop of measurement higher up ground surface [grand] Side by side, the different components of this formula are calculated. Equally the magnitude of the day or x-mean solar day soil heat flux (M) beneath the grass reference surface is relatively small, information technology is ignored. The net radiations (Rn) is the difference between the incoming net shortwave radiation (Rns) and the outgoing net longwave radiation (Rnl). The cyberspace shortwave radiation (Rns) is calculated as follows: where: Rns  : net shortwave radiations [MJ.thousand-2.day-1] α  : albedo or awning reflection coefficient, which is 0.23 for the hypothetical grass reference crop [dimensionless] Rs  : incoming shortwave radiation [MJ*chiliad-2* day-1] The outgoing net longwave radiation (Rnl) is calculated equally follows. First clear-sky radiation (Rso) is derived: where: Rso  : clear-sky radiation [MJ.chiliad-2.twenty-four hour period-1] z  : station elevation to a higher place sea level [m] Ra  : extraterrestrial radiation, Angot radiation [MJ.k-two.24-hour interval-1] Then, the approachable cyberspace longwave radiation (Rnl) is calculated: where: Rnl  : approachable internet longwave radiations [MJ.g-ii.solar day-ane] σ  : Stefan-Boltzmann constant [4.903 10-ix MJ.Yard-4.m-ii.day-1] Ra  : extraterrestrial radiation, Angot radiation [MJ*m-ii* day-1] Tmax  : maximum absolute temperature during the 24-hr menstruation [ °C + 273.16] Tmin  : minimum absolute temperature during the 24-hour period [ °C + 273.sixteen] ea  : actual vapour pressure [kPa] Rs/Rso : relative shortwave radiations (limited to 1.0) [dimensionless] The psychrometric constant is corrected for atmospheric pressure: where: P  : atmospheric pressure [kPa] z  : top above sea level [yard] where: γ  : psychrometric abiding [kPa °C-i] λ  : latent estrus of vaporization, ii.45 [MJ.kg-one] cp  : specific heat at constant pressure, one.013 ten-3 [MJ.kg-ane.°C-1] Є  : ratio molecular weight of h2o vapour/dry air 0.622 Next, saturated-vapour-pressure is calculated for both the minimum and maximum temperature and averaged after: where: e°(T)  : saturation vapour pressure at the air temperature T [kPa] T  : air temperature [°C] Finally, the slope of the saturation vapour pressure bend is determined (first the minimum and maximum temperature are averaged to obtain the average temperature): where: Δ  : gradient of saturation vapour pressure curve at air temperature T [kPa °C-1] T  : air temperature [°C] ++ Penman ++ The Penman-Monteith algorithm is valid only for a reference canopy (ET0) and therefore it is not used to summate the reference values for bare soil and open h2o (ES0, E0). The groundwork is that the Penman-Monteith model is basically a surface energy remainder where the cyberspace solar radiation is partitioned over latent and sensible rut fluxes (ignoring the soil oestrus flux). To estimate this division, the method links betwixt the surface and air temperature. However, the assumptions underlying the model are valid but when the surface where this partitioning takes identify is the same for the latent and sensible oestrus fluxes. For a crop awning this assumption is valid because the leaves of the canopy grade the surface where both latent rut flux (through stomata) and sensible estrus flux (through leaf temperature) are partitioned. For a soil, this principle does not piece of work because when the soil is drying the evaporation front will quickly disappear below the surface and therefore the assumption that the sectionalization surface is the same does not concord anymore. For h2o surfaces, the assumptions underlying Penman-Monteith do not concur because there is no direct relationship betwixt the temperature of the water surface and the cyberspace incoming radiation as radiation is absorbed by the water column and the temperature of the h2o surface is co-determined by other factors (mixing, etc.). Only for a very shallow layer of water (ane cm) the Penman-Monteith methodology could be applied. For blank soil and open up water the Penman model is preferred. Although it partially suffers from the same problems, information technology is calibrated somewhat better for open h2o and blank soil based on its empirical wind office. Finally, in crop simulation models the open water evaporation and bare soil evaporation merely play a modest office (pre-sowing weather and flooded rice at early stages), it is non worth investing much effort in improved estimates of the reference values. Evapotranspiration from a wet bare soil surface (ES0) and from a h2o surface (E0) is calculated with the Penman formula (Penman, 1948). Merely the albedo and surface roughness differs for these two types of evapotranspiration as explained below: where: E0 : evapotranspiration from a water surface [mm*d-ane] Rna : net absorbed radiation [mm*d-1] EA : Evaporative need [mm*d-1] Δ : Slope of the saturation vapor pressure level curve [mbar*C-1] γ : Psychometric constant (0.67) [mbar*C-1] The net absorbed radiation depends on incoming global radiation, net outgoing long-wave radiations, the latent oestrus and the reflection coefficient of the considered surface (albedo). For ES0 and ET0 albedo values of 0.15 and 0.xx are used respectively. The evaporative demand is determined past humidity, air current speed and surface roughness. For a gratuitous water surface and for the moisture bare soil (E0, ES0) a surface roughness value of 0.5 is used. For a more detailed description of the underlying formulae we refer to Supit et al. (1994) and van der Goot (1997). Annotation that coefficients of the Angstrom method are required to calculate the atmospheric transmission within the adding of the net outgoing long wave radiation.

Calculated E0, ES0, and ET0 are stored in object WEATHER_OBS_STATION_CALCULATED.

Letters to the Project Direction Board

Information on successfull completion of the diverse processing steps is sent to the Project Management Board (PMB).

List of signals communicated to the Project Management Lath (PMB) in connexion to the processing of observations from basis weather stations.
EVENT_ID Region FREQUENCY Filibuster Hour MINUTE THEME STEP RESOLUTION LOCATION 310 EUR Daily 1 19 0 Weather - OBS Delivered Station FTP WENR 303 EUR Daily 1 19 0 Weather - OBS - 6HourlyRain Delivered Station FTP WENR 304 EUR Daily ane nineteen 0 Weather - OBS - 3HourlyRain Delivered Station FTP WENR 200 CHN Daily 1 xix 0 Weather - OBS Delivered Station FTP WENR

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