CHINA SOIL MOISTURE DATA Plant Available Soil Moisture Gravimetric Observations and maps, 1981-91 Alan Robock Department of Environmental Sciences Rutgers, The State University of New Jersey Jared Entin Hydrological Sciences Branch, NASA-GSFC Konstantin Vinnikov Department of Meteorology, University of Maryland Suxia Liu Department of Hydrology, Institute of Geography, Chinese Academy of Sciences, Bejing 1. DESCRIPTION OF THE DATA SET The Chinese data set consists of 43 stations in China, for the period 1981-91, described in detail by Entin et al. (1999a). These data have already been used by Entin et al. (1999b) to evaluate the Global Soil Wetness Project soil moisture model calculations and by Entin et al. (1999c) to study the scales of soil moisture variations. Soil moisture observations were taken using the gravimetric technique for each 10-cm layer down to a depth of 1 m, with the first layer divided into two 5-cm layers. The data were observed three times a month on the 8, 18 and 28th days, for the full year. There is a variety of vegetation present in the network, but all of them fall into either the agriculture or grassland category. The data were originally recorded as percent wetness by mass of dry soil. Using soil density information available for each layer at each site, we determined the volumetric soil moisture. In addition, the wilting level of each layer was measured in terms of percent wetness by mass of dry soil and then converted, again by using the soil density, into a volumetric measure. This value was subtracted from the soil moisture observation to obtain the plant-available soil moisture (W) for each layer. For some of the stations the wilting levels appear to be too high, necessitating caution in use. We are in the process of obtaining corrected values. In the the meantime, we suggest not using these stations for the absolute amount of soil moisture. Otherwise, please contact us for ideas about how to improve the estimates of wilting level. Stations with such high wilting levels have been marked with "*" in the station list. The layers were subsequently added together to give top 10 cm, top 50 cm, and top 1 m W, for the GrADS files. Time series data corresponding to each individual layer are available for downloading in both GrADS and ASCII formats. GrADS files for spatial plots are also available. Wilting level data corresponding to each soil layer are also available. Clickable links to download the data are at the bottom of this page, after descriptions of the file formats. 2. DATA SET IN ASCII FORMAT These data are archived in the file soilm_china.dat. Data are written as year, month, date, and 11 layers with the FORTRAN 21 format(4X,A12,4X,I5,3X,I4,1X,I4,2X,F6.2,3X,F6.2) 31 format(6X,11(1X,f6.2)) This file contains data for the dates 8, 18, and 28 of each month from 1981 to 1991. Missing data are indicated by code -99.99. A FORTRAN program to read these data is in the file read.f. Wilting levels corresponding to each soil layer and top 1m of the soil are in the file wiltlev_china.dat. A list of the 43 stations with their station IDs is given in the file list43_china.txt. 3. GrADS FILES GrADS control and data files consisting time series for 10 cm, 50 cm and 1 m depths for all the 43 stations can be also downloaded for visualization. The files are china*.ctl, where * is either 10cm, 50cm or 1m. GrADS executable china.x could be used to display the time-series. This could be done by running the GrADS exec file china.x with any one of the station numbers listed as variables in the GrADS .ctl files. These files can be downloaded through anonymous ftp as follows: ftp climate.envsci.rutgers.edu login as: anonymous password: your e-mail aress cd pub/soil_moisture/CHINA/Grads/ bin prompt mget * bye ftp://climate.envsci.rutgers.edu/pub/soil_moisture/CHINA/Grads/ 4. REFERENCES Entin, J.K., A. Robock, S. Liu, K.Y. Vinnikov, and G. Peng., 1999a: Temporal and spatial variations in soil moisture in China, J.Climate, in preparation. Entin, Jared, Alan Robock, Konstantin Y. Vinnikov, Shuang Qiu, Vladimir Zabelin, Suxia Liu, A. Namkhai, and Ts. Adyasuren, 1999b: Evaluation of Global Soil Wetness Project soil moisture simulations. J. Meteorol. Soc. Japan, in press. Entin, Jared K., Alan Robock, Konstantin Y. Vinnikov, Steven E. Hollinger, Suxia Liu, and A. Namkhai, 1999c: Temporal and spatial scales of observed soil moisture variations in the extratropics. Submitted to J. Geophys. Res. 5. IF YOU HAVE ANY PROBLEMS OR QUESTIONS, PLEASE CONTACT US FOR ASSISTANCE: Dr. Konstantin Ya. Vinnikov OR Prof. Alan Robock Department of Meteorology Department of Environmental Sciences University of Maryland Rutgers, The State University of New Jersey College Park, Maryland 20742 USA New Brunswick, New Jersey 08901 USA Phone: (301) 405-5382 Phone: (732) 932-9478 Fax: (301) 314-9482 Fax: (732) 932-8644 E-mail: kostya@atmos.umd.edu E-mail: robock@envsci.rutgers.edu OR OR Dr. Jared Entin Dr. Mingquan Mu Hydrological Sciences Branch Department of Environmental Sciences NASA-GSFC, Building #33, Mail Code 974 Rutgers, The State University of New Jersey Greenbelt MD 20771 New Brunswick, New Jersey 08901 USA Phone: (301)-614-5825 Phone: (732) 932-9735 Fax: (301)-614-5808 Fax: (732) 932-8644 E-mail: Jared.Entin@gsfc.nasa.gov E-mail: mu@envsci.rutgers.edu Prepared by Alan Robock (robock@envsci.rutgers.edu) and Mingquan (mu@envsci.rutgers.edu) Last updated on April 27, 2001