NOAA/ATOVS Data Obtaining, Processing and Displaying Based on DVB-S System

DVB-S (digital video broadcast by satellite) remote sensing satellite data sharing platform is essentially a data transmission system which collects the data from DB (direct broadcast) acquisition stations and re-broadcasts by a communication satellite in near real time. On the current DVB-S system in China, CMA/NSMC broadcasts the data free of charge not only of the required EOS/MODIS data from both CMA (Beijing, Guangzhou, Urumchi and Lhasa) and SOA (Beijing and Sanya) DB receiving stations, but also all the FY-1/HRPT and NOAA/HRPT data of CMA (Beijing, Guangzhou, and Urumchi) 3 DB stations in very short time through a rented geostationary communication satellite (ChinaStar-1). Users in China and East-Asia area have the benefit of this DVB-S data sharing platform. The DVB-S system in user-end consists of three parts: receiving PC with data ingest card and a small dish; data pre-processing PC, data product and application.ATOVS, a set of vertical sounding instruments aboard on NOAA series satellites (NOAA 15 and later), with its data stored in HRPT data stream, has 40 channels covering spectrum of visible, infrared and microwave bands for atmosphere temperature and moisture sounding. ATOVS consists of 3 independent instruments: HIRS/3, AMSU-A and AMSU-B. It can be greatly improved on atmospherical temperature profile by using HIRS/3 and AMSU-A combination as well as on moisture profile with HIRS/3 and AMSU-B retrieval together, particular in cloud area. In addition, the window channels in AMSU-A and AMUS-B can be improved on the surface sounding ability of NOAA satellite, such as more precise atmosphere precipitable water and some the surface products.ATOVS data receiving, processing and displaying systems at the DVB-S user-end are introduced briefly. The ATOVS data processing system includes the software of pre-processing (AAPP) and retrieval packages (IAPP). The original AAPP software (AVHRR & ATOVS Pre-processing Package) is developed by EUMSAT under UNIX or LINUX operational system, and here the modified AAPP has been transferred into PC/WinXP/2000. It includes 4 steps to pre-process ATOVS data: decommutation, geolocation, calibration and re-preprocessing. ATOVS level 1c data (HIRS/3, AMSU-A, and AMSU-B stored as temperature brightness by channels) produced by AAPP package can be directly applied to NWP or some variable assimilation models. If user wants to get some meteorological elements such as temperature profile, moisture profile, total ozone amount from ATOVS instruments, the IAPP (International ATOVS Processing Package from Wisconsin, USA) software must be executed. Here the IAPP is also modified from UNIX into PC/WinXP/2000. The accuracy of temperature and moisture profiles in DVB-S ATOVS system is similar to the result of the running operational system in NSMC. The RMS compared with RAOB data is 2K less for temperature and 20% for moisture, respectively. NSMC also develops ATOVS data displaying system under PC/WinXP/2000. It is easy for users to use the software displaying and analyzing ATOVS retrieval data as the temperature and moisture profiles, contour lines, vertical section planes, elements and so on.Examples of typhoon Crabapple in July 2005 and a heavy rain in June 2002 are selected for displaying and analyzing, the extraordinary advantages of meteorological satellite vertical sounding are presented by the ATOVS displaying system. The completed DVB-S system is sure to make the applications of ATOVS data in meteorological and related fields even more effectively.