A Sampling Technique of Typical Atmospheric Profiles Database in China

Atmospheric profiles are important input parameters in simulation of atmospheric radiative transfer, emulation of new satellite instruments spectral characteristics, development of transmittance model, retrieval of atmospheric parameters and the assimilation of satellite data in numerical weather prediction. It is very necessary that built a sampled atmospheric profiles database to meet many kinds of application requirements. The quantity, covering region, and source of atmospheric profiles affect the efficiency and results of application a lot. A major attempt to sample atmospheric profiles on a global scale has been the constitution of successive versions of the Thermodynamic Initial Guess Retrieval database (TIGR), despite the high dimensionality. Each version groups together hundreds of profiles sampled from mass soundings observations of the atmosphere. There are dozens of atmospheric profiles database currently, but profiles in China region are very deficient. An atmospheric profiles database with samples in China region can enhance the accuracy in calculation of radiative transfer and profiles retrieval. 61308 profiles of year 2002 are collected as a preparatory database that includes 124 radiosond station measurement distributing in China region through Meteorological Data Storage System, and a database is set up comprising 30 atmospheric temperature and humidity profiles and named it CRASD 2 (China Regional Atmospheric Sample Database 2) with topology method. It is classified by surface pressure and divided into 5 groups and their respective surface pressure are 500 hPa, 700 hPa, 850 hPa, 925 hPa, 1000 hPa.The CRASD 2 covers the four seasons of one year and the two radiosond observation time of 00:00 and 12:00, so that it has characteristics of well proportioned time and season range. Considering the vertical height range it contains the samples located in stations with the altitude of several to several thousand meters. Besides, the profiles in this database distribute in large overcast geographical region of China, and the profiles with large discrepancy distribute in north—east, north—west and south region, while samples with relative less difference mostly are located in south of the Yangtze River and Yellow and Huai River region. The diversity between profiles mainly exist in the different height of tropopause, discrepancy in atmospheric temperature and humidity condition of the same pressure level, and the existence of temperature inversion layer. With the independency between profiles and good climate representative, the CRASD 2 database is accord with the principle of a sampled database, so it can support the application of atmosphere samples in research of radiative transfer and remote sensing retrieval. This elementary employment of topology sampling technique in extracting regional profiles database implies it may support sampling database from longer time serial observation data, and adding more profiles variables in sampling method in the future work.