User's Guide for China Meteorological Forcing Dataset

 

Kun Yang, Prof., Dr. (yangk@itpcas.ac.cn)

Data Assimilation and Modeling Center for Tibetan Multi-spheres (DAM)

Institute of Tibetan Plateau Research (ITP), Chinese Academy of Sciences (CAS)

 

1. Introduction

The China Meteorological Forcing Dataset was produced by merging a variety of data sources. This data sets contains the parameters with temporal resolution of 3-hr,covers the period 1981-2008,on a 0.1°x0.1° grid,and the parameters with temporal resolution of 3-hr,covers the period 1996-2006,on a 0.25°x0.25° grid.The data sets can be used for hydrological modeling, land surface modeling, land data assimilation, and other terrestrial modeling.

2. Variables

Variables

Variable name

Unit

Pysical meaning

Temperature

temp

K

Instantaneous near surface air temperaute.

Pressure

pres

Pa

Instantaneous near surface air pressure.

Specific humidity

shum

kg kg-1

Instantaneous near surface air specific humidity.

Wind speed

wind

m s-1

Instantaneous near surface wind speed.

Downward shortwave radiation

srad

W m-2

3-hourly mean (from -1.5hr to +1.5hr) surface downward shortwave radiation.

Downward longwave radiation

lrad

W m-2

3-hourly mean (from -1.5hr to +1.5hr) surface downward longwave radiation.

Precipitation rate

prec

mm hr-1

3-hourly mean (from -3.0hr to 0.0hr) precipitation rate.

 

3. Data archive and access

The data with the spatial resolution and the temporal resolution of of 0.1 deg, 3-hr is saved as follow:

 

(1)Each data file is named as VVVV_YYYYMM.nc (e.g. temp_198101.nc), where VVVV is the abbreviation of variable name, YYYY is the four-digital year, MM is the two-digital month, that means one file contains data of only one variable for only one month, additionally, .nc is the file name suffix which indicates that the data were stored as NetCDF format;

(2)Each file is compressed as .gz format in order to save disk space, users must uncompress these data files before using them. Recommended software to do this is gunzip (on UNIX/Linux) or WinRAR (on Windows);

(3)A simple Fortran program named nc_read.f90 is provided along with the dataset as a sample to show how to read the NetCDF data files, but users might have to modify it to satisfy special needs. This program has been tested on Linux and Windows platform with netcdf-3.x libraries, and anyone who wants to compile this program must have NetCDF library installed first. For more information about NetCDF, please see http://www.unidata.ucar.edu/software/netcdf.

(4)An mask file named mask.nc is also provided along with this dataset, which has same grid distribution as the data product. In this file, grid points locate at China's land give values of 1, while the other grid points give values of 0. Another file named talt.nc is identical to mask.nc, but for terrain altitude.

 

The data with the spatial resolution and the  temporal resolution of of 0.25 deg, 3-hr is saved as follow:

 

This data set is similar to the  previous one,just with a different storage format.

Each data file is named asYYYYMMDDHH.grd (e.g. temp_198101.nc), where YYYY is the four-digital year, MM is the two-digital month, DD is the two-digital day, HH is the two-digital hour,that means one file contains data of all the 7 variables for a time ,  additionally, .grd is the file name suffix which indicates that the data were stored as Binary format;

4. Data Acknowledgement

(1)References

Kun Yang, Jie He, Wenjun Tang, Jun Qin, CCK Cheng, 2010: On downward shortwave and longwave radiations over high altitude regions: Observation and modeling in the Tibetan Plateau. Agric. Forest. Meteorol, 150, 38-46.

 

 

Chen, Y-Y, K. Yang, J. He, J. Qin, J-C Shi, J-Y Du, Q. He, 2011: Improving land surface temperature modeling for dry land of China. J.Geophys.Res.,116,D20104,doi:10.1029/2011JD015921.

 

(2)To recognize the valuable role of the data provider, the data's origin must be acknowledged ("The forcing dataset used in this study was developed by Data Assimilation and Modeling Center for Tibetan Multi-spheres, Institute of Tibetan Plateau Research, Chinese Academy of Sciences").

To facilitate the maintenance and improvements of the dataset, please send a copy of scientific publications to the data provider via email (yangk@itpcas.ac.cn).

5. Disclaimer

Although we have made great efforts to control input data and improve the forcing dataset, the accuracy and reliability of these data are subject to the availability of in situ data and is not guaranteed in any way. The data provider disclaims liability of any kind whatsoever, including, without limitation, liability for quality, performance, and fitness for a particular purpose arising out of the use.