



IFS documentation Front Page
Table of contentsCHAPTER 1 Incremental
formulation of 3D/4D variational assimilationan overview CHAPTER 2 3D variational assimilation CHAPTER 3 4D variational assimilation CHAPTER 4 Background term CHAPTER 5 Conventional observational
constraints CHAPTER 6 Satellite observational
constraints CHAPTER 7 Background, analysis
and forecast errors CHAPTER 8 Gravitywave control CHAPTER 9 Data partitioning (OBSORT) CHAPTER 10 Observation screening CHAPTER 11 Analysis of snow CHAPTER 12 Land surface analysis CHAPTER 13 SST and seaice analysis CHAPTER 14 Reducedrank Kalman filter 
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Section Previous Section 5.6 The observation operator for temperatureTemperature is interpolated linearly in pressure (PPINTP), in the routine PPT. Above the highest model level the temperature is kept constant and equal to the value of the highest model level. Between the lowest model level and the model's surface the temperature is interpolated linearly, using:
Below the lowest model level the temperature is extrapolated by
with , for , but is modified for high orography to , where
for , and
for . If then is reset to zero. The two temperatures and are computed using Eqs. (5.6) to (5.9). Next Section Previous Section 



