CFSR Radiosonde Radiation Bias Correction

•Four separate operational tables used

•Creates discontinuities in temp analysis

•Interact with variational satellite bias corrections

•Highlights the need to use a more continuous radiosonde correction in CFSRL, as in R1(pre79), ERA, JRA, MERRA

•R1 used monthly F-O statistics to update radiosonde bias corrections by WMO block number before 1979

•So, port the R1 algorithm to CFSRL

•Constrain the monthly corrections as documented in ERA40 which used a similar adaptive procedure

•Also, look at the Haimberger corrections for the pre-satellite era. (83K+ days of corrections for a fixed set of individual stations) MERRA used modified R1 algorithm plus Haimberger corrections

Plan for CFSRL adaptive RAOB correction

Each month the composite (F-O) statistics for temperature are computed for each WMO block (01-99)

A profile of percentages of the (F-O) stats is defined as follows:pob>=700 tfrac=0pob==500 tfrac=.8*.333pob==400 tfrac=.8*.666pob< 400 tfrac=.8

A data density factor is defined: ddf=min(1,cnt/15)

A limiting factor is defined: abs(cor)<=tfrac*2.5

Next months corrections in each block is defined as: cor=(O-F)*tfrac*ddf.

Finally the absolute value of the correction is limited to be <=tfrac*2.5.

Adaptive procedure devised for CFSRL

---------------------------------------- ---------------------------------------- | 71 1.0 .0 .0 .0 .0 | 72 1.0 .0 .0 .0 .0 || 71 2.0 .0 .0 .0 .0 | 72 2.0 .0 .0 .0 .0 || 71 3.0 .0 .0 .0 .0 | 72 3.0 .0 .0 .0 .0 || 71 5.0 1.0 .0 .8 .0 | 72 5.0 .0 .0 .1 .0 || 71 7.0 -.5 .0 -.6 -.2 | 72 7.0 .0 .0 -.4 -.1 || 71 10.0 -.9 .0 -.9 -.4 | 72 10.0 -.4 -.2 -.6 -.3 || 71 20.0 -.2 .0 -.3 -.1 | 72 20.0 -.1 .1 -.2 -.3 || 71 30.0 -.1 .0 -.1 -.3 | 72 30.0 .0 -.3 -.1 -.4 || 71 50.0 .0 .0 -.1 .2 | 72 50.0 .0 .1 -.1 -.2 || 71 70.0 -.1 .0 -.2 -.1 | 72 70.0 -.1 .4 -.1 -.3 || 71 100.0 -.1 .0 -.1 -.1 | 72 100.0 .2 .2 .1 -.2 || 71 150.0 .0 -.1 -.1 .0 | 72 150.0 .2 -.1 .2 .0 || 71 200.0 .1 .0 .0 .3 | 72 200.0 .6 .2 .6 .4 || 71 250.0 .4 .1 .3 .2 | 72 250.0 .4 -.1 .4 .2 || 71 300.0 .2 .1 .2 .0 | 72 300.0 .2 -.1 .3 .1 || 71 400.0 .1 -.1 .1 .0 | 72 400.0 .1 -.1 .1 .1 || 71 500.0 .1 .0 .1 .0 | 72 500.0 .1 .0 .1 .1 || 71 700.0 .0 .0 .0 .0 | 72 700.0 .0 .0 .0 .0 || 71 850.0 .0 .0 .0 .0 | 72 850.0 .0 .0 .0 .0 || 71 925.0 .0 .0 .0 .0 | 72 925.0 .0 .0 .0 .0 || 71 1000.0 .0 .0 .0 .0 | 72 1000.0 .0 .0 .0 .0 | ---------------------------------------- ----------------------------------------

Sample corrections in blocks 71-72 for Jul 2010

Haimberger (2006) day-night bias detection illustration