Introduction and Quality Analysis of Chinese Aircraft Meteorological Data

Meteorological data observed on civil airplanes in China in recent years is all the AMDAR reports spark plugged to obtain by the AMDAR Program of WMO. For a comprehensive understanding of the current situation and quality of Chinese aircraft meteorological data, the temporal and spatial distribution character of Chinese AMDAR data from 2003 to 2009 are summarized, synthesizing the AMDAR reports of these six years observed through aircrafts taking off and landing phase to aircraft observational profiles and analyzing its usability. Moreover, in reference to the aircraft data quality control principium used by NCEP, the quality of global AMDAR data and Chinese AMDAR data from May 2003 to April 2009 are checked with a quality control method, which consists of six steps: Metadata check, validity check of air temperature and wind, aviation track organization, position consistency check, temporal consistency check of air temperature and attitude, and comprehensive analysis of quality control code. Based on the result of quality control, the temporal and spatial distribution characteristic of error data is analyzed. The statistical result shows that, the amount of Chinese AMDAR reports has been increasing year by year. In 2003, there are about 50000 files per month. In 2009, the number is about 200000 per month. Two thirds of the reports concentrate in take off and landing phase. The analysis result shows that, all of the aircraft observational profiles cover over 110 airports, which are mainly distributed in the east central areas, especially some large and medium cities. The vertical resolution of almost all the aircraft observational profiles is higher than 10 hPa. With the development of Chinese AMDAR program, the proportion of profiles with high resolution increases year by year. In 2008, there are about 78.9 percent aircraft observational profiles whose vertical resolution is higher than 2 hPa. Case study result shows that, although the vertical trend is very close, there is a little difference at low level between the temperature observed by aircraft and by radiosonde. In addition, there is also a little difference among the temperature observed at the same height by different aircrafts. The result of quality control shows that the temperature error rate of Chinese AMDAR data is lower than the global level, but the wind error rate is to the contrary. The error data is mainly concentrated in the near surface level. The quality of Chinese AMDAR data has improved significantly compared with previous years. From January 2008 to April 2009, the monthly error rate of wind speed is less than 1.3 percent, and the monthly error rate of temperature is less than 0.2 percent. In conclusion, the source and quality of Chinese aircraft meteorological data is stable，and as an important part of upper air observation data, aircraft meteorological data is of great application value.