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ISLSCP Initiative II Home General Data Overview Near-Surface Met Data Overview |
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ISLSCP Initiative II |
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Near-Surface Meteorology Data
The ECMWF (European Centre for Medium-range Weather Forecasts) near-surface meteorology data set for the ISLSCP Initiative II data collection has been derived from the ECMWF 40-year re-analysis, or ERA40 (Simmons and Gibson, 2000), which covers the years 1957 to 2001. The purpose of ERA40 is to produce an objective analysis of the atmosphere making optimal use of a wide range of observing systems. A recent version of the ECMWF Numerical Weather Prediction system (cycle 23r4) is used for the entire analysis period. The advantage of re-analysis over operational analysis is that no system changes occur that might affect the analysis products, although there are significant changes in the observations. For more general details on the ERA40 project the users should see http://www.ecmwf.int/research/era [Internet Link].
The surface dataset provided here has been extracted from the complete ERA40 1957-2001 archive and processed onto the ISLSCP II Earth grid. All variables in this dataset are provided on an Earth grid with a spatial resolution of 1 degree in both latitude and longitude and span the common ISLSCP II period from 1986 to 1995. Variables are provided with fixed, monthly, monthly-6-hourly and monthly-3-hourly (i.e. monthly mean diurnal cycle), 6-hourly, and 3-hourly temporal resolutions. See the tables below for a complete listing of all the parameters provided here.
At this revision the fixed, monthly and monthly 6-hourly data are available on this Web site (http://islscp2.sesda.com/). Because of file sizes and bandwidth limitations, all the ECMWF data, including the monthly-3-hourly, 6-hourly, and 3-hourly data will be made available through the Goddard Space Flight Center (GSFC) Distributed Active Archive Center (DAAC) at http://daac.gsfc.nasa.gov/www/islscp/ [Internet Link]. The 3-hourly data will be distributed at the GSFC DAAC only through a Distributed Oceanographic Data System (DODS) server.
Data Provider: Anton C.M. Beljaars, Alan K. Betts, Eric Brown de Colstoun
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****ECMWF DATA USE POLICY**** User should take note of the restrictions limiting the use of these data to research and educational purposes, outlined in document ecmwf_data_use_policy.pdf. Users must read and understand the conditions of use before using the ERA40 data provided here. ********************* |
 Diurnal 6-hourly, Monthly Data Files (stored on this site) |
Diurnal 3-hourly, 6-hourly Data Files (stored at the Goddad DAAC) |
 Data Set Documentation |
 Image Viewing Tutorial |
The files have been compressed using the PKZip program. Each uncompressed file contains space-delimited ASCII text with 360 values per line and 180 lines of data (1 degree resolution). Each line is terminated by a newline character. The data are structured so that the upperleft corner of the first pixel is located at 90 North latitude and 180 West longitude. Each pixel represents a 1 by 1 degree area. These files are labeled with "_1d_". The following parameters are available at the following time scales:
Fixed Time Scale [stored on this site]
| Abbrev. | Variable | Units |
|---|---|---|
| SR | Surface roughness length for momentum | m |
| LSRH | Logarithm of surface roughness length for heat | unitless |
| AL | Albedo background (climatological monthly mean) | unitless |
| Z | Geopotential of model surface (Orography * g) | m2/s2 |
| LSM | Land/Water mask used to process data | na |
| MASK_DIF | Differences between the ISLSCP-2 land/water mask and the original land/water mask above | na |
| CVL | Low vegetation fraction | unitless |
| CVH | High vegetation fraction | unitless |
| TVL | Low vegetation dominant type | unitless |
| TVH | High vegetation dominant type | unitless |
Monthly Mean (Analyses) [stored on this site]
| Abbrev. | Variable | Units |
|---|---|---|
| SD | Snow Depth | m of water |
| ASN | Snow Albedo | unitless |
| RSN | Snow Density | kg/m3 |
| TSN | Snow Temperature | degrees K |
| SWL1 | Soil Moisture Layer 1 | m3/m3 |
| SWL2 | Soil Moisture Layer 2 | m3/m3 |
| SWL3 | Soil Moisture Layer 3 | m3/m3 |
| SWL4 | Soil Moisture Layer 4 | m3/m3 |
| STL1 | Soil Temperature Layer 1 + Sea Surface Temperature (SST) over Ocean | degrees K |
| STL2 | Soil Temperature Layer 2 + SST | degrees K |
| STL3 | Soil Temperature Layer 3 + SST | degrees K |
| STL4 | Soil Temperature Layer 4 + SST | degrees K |
| CI | Sea Ice Fraction | percent |
| SMIR | Soil Moisture Availability Index (Root Zone) | unitless |
| SMIB | Soil Moisture Availability Index (Bare Soil) | unitless |
Monthly Mean Precipitation (Forecasts) [stored on this site]
| Abbrev. | Variable | Units |
|---|---|---|
| LSP | Large Scale Precipitation Rate | mm/s |
| CP | Convective Precipitation Rate | mm/s |
| SF | Snow Fall Rate | mm/s |
| TOTP | Total Precipitation Rate | mm/s |
Monthly 6-hourly (Mean 6-hour Diurnal Cycle) (Analyses) [stored on this site]
| Abbrev. | Variable | Units |
|---|---|---|
| 2T | Temperature at 2m level | degrees K |
| 2D | Dew point at 2m level | degrees K |
| 10U | U-component of wind speed at 10m | m/s |
| 10V | V-component of wind speed at 10m | m/s |
| 10S | Horizontal wind speed at 10m | m/s |
| U57 | U-component of wind speed at level 57 | m/s |
| V57 | V-component of wind speed at level 57 | m/s |
| T57 | Temperature at level 57 | degrees K |
| Q57 | Specific humidity at level 57 | kg/kg |
| U60 | U-component of wind speed at level 60 | m/s |
| V60 | V-component of wind speed at level 60 | m/s |
| T60 | Temperature at level 60 | degrees K |
| Q60 | Specific humidity at level 60 | kg/kg |
| LNP | Surface Pressure | Pa |
Monthly 3-hourly (Mean 3-hour Diurnal Cycle) (Forecasts) [stored at the Goddard DAAC]
| Abbrev. | Variable | Units |
|---|---|---|
| 2T | Temperature at 2m level | degrees K |
| 2D | Dew point at 2m level | degrees K |
| 10U | U-component of wind speed at 10m | m/s |
| 10V | V-component of wind speed at 10m | m/s |
| 10S | Horizontal wind speed at 10m | m/s |
| LNP | Surface Pressure | Pa |
| EWSS | U stress | N/m2 |
| NSSS | V stress | N/m2 |
| SSR | Surface net shortwave (SW) radiation | W/m2 |
| STR | Surface net longwave (LW) radiation | W/m2 |
| SSRD | Surface SW downward | W/m2 |
| STRD | Surface LW downward | W/m2 |
| TSR | Top-of-Atmosphere (TOA) net SW radiation | W/m2 |
| TTR | TOA net LW radiation | W/m2 |
| SSHF | Surface sensible heat flux | W/m2 |
| SLHF | Surface latent heat flux | W/m2 |
| E | Surface evaporation rate | mm/s |
| ES | Snow evaporation rate | mm/s |
| SMLT | Snowmelt Rate | mm/s |
| LSP | Large Scale Precipitation Rate | mm/s |
| CP | Convective Precipitation Rate | mm/s |
| SF | Snow Fall Rate | mm/s |
| RO | Runoff Rate | mm/s |
6-hourly (Analyses) [stored at the Goddard DAAC]
| Abbrev. | Variable | Units |
|---|---|---|
| 2T | Temperature at 2m level | degrees K |
| 2D | Dew point at 2m level | degrees K |
3-hourly (Forecasts) [not available yet]
| Abbrev. | Variable | Units |
|---|---|---|
| 2T | Temperature at 2m level | degrees K |
| 2D | Dew point at 2m level | degrees K |
| 10U | U-component of wind speed at 10m | m/s |
| 10V | V-component of wind speed at 10m | m/s |
| U57 | U-component of wind speed at level 57 | m/s |
| V57 | V-component of wind speed at level 57 | m/s |
| T57 | Temperature at level 57 | degrees K |
| Q57 | Specific humidity at level 57 | kg/kg |
| U60 | U-component of wind speed at level 60 | m/s |
| V60 | V-component of wind speed at level 60 | m/s |
| T60 | Temperature at level 60 | degrees K |
| Q60 | Specific humidity at level 60 | kg/kg |
| LNP | Surface Pressure | Pa |
| SKT | Skin Temperature | degrees K |
| EWSS | U stress | N/m2 |
| NSSS | V stress | N/m2 |
| SSR | Surface net SW radiation | W/m2 |
| STR | Surface net LW radiation | W/m2 |
| SSRD | Surface SW downward | W/m2 |
| STRD | Surface LW downward | W/m2 |
| SSHF | Surface sensible heat flux | W/m2 |
| SLHF | Surface latent heat flux | W/m2 |
| E | Surface Evaporation Rate | m/s |
| LSP | Large Scale Precipitation Rate | mm/s |
| CP | Convective Precipitation Rate | mm/s |
| SF | Snowfall Rate | mm/s |
| RO | Runoff Rate | mm/s |
Related Pages:
ISLSCP Initiative II Home
General Data Overview
Near-Surface Met Data Overview
ECMWF Near-Surface Meteorology Parameters
Revision Date: November 22, 2004