# Presentation: 369410

## Assimilation of Precipitation at the Meteorological Service of Canada

- G. Deblonde, J.-F. Mahfouf, B. Bilodeau, D. Anselmo

- 4th GPM Planning Workshop
- June 15-17, 2004
- Greenbelt, Maryland

## Outline

- 1D-Var Tb  Methodology (Moreau et al. 2003)
- Results of 1D-Var Tb analyses for Tropical Cyclone Zoe and Super-typhoon Mitag
- Impact of  T background error variance

## Tb 1D-Var

**T(z), Q(z) , {dT/dt, dQ/dt}**

**Brightness Temperatures**
**RTTOVSCATT**
**Eddington Approximation**
**(Bauer &  Moreau ECMWF)**

**MOIST PHYSICS **
**(CONVECTION &**
**LARGE-SCALE CLOUD SCHEMES)**

**Observed Tb FROM: **
**SSM/I****, ****TMI**
**SSMIS,  AMSR-E, **
**EGPM, GPM**

**Tb 1D-Var**

**Convection Scheme:**** **
**Kain-Fritsch**** ****(or**** ****ECMWF Mass-Flux)**
**Large-scale cloud scheme:**** **
**CLOUDST-Tompkins & Janiskova 2003**
**	****	****ECMWF **

**LIQUID AND ICE WATER CONTENTS (z), **
**RAIN FLUX (z),  SNOW FLUX (z), **
**CLOUD FRACTION (z)**

**Jacobians:**
- RTTOVSCATT:    Adjoint
- Cloud Schemes:   Finite Difference

**Observation Operator**
**           ****Tb=*****H*****(X)**

**X=[T,lnQ]**

- (Moreau et al. 2003)

## BACKGROUND TERM

- GLOBAL MODEL: 800 (longitude) x 600 (latitude)
-  0.45ox 0.3o grid resolution
- 58 vertical levels (top at 10 hPa)
- Time-step= 15 minutes
- Kain-Fritsch (CAPE) and CONSUN (Sundqvist variant)
- 12h precipitation spin-up

- 1D-Var Background = 12h forecast

**GEM MESOGLOBAL CONFIGURATION**

## Background Errors

- Correlation of T and lnQ background errors from 24-48h forecasts of GEM mesoglobal (C. Charette)
- σT=1 K
- σQ  computed from empirical formula as done at ECMWF (Rabier et al. 1998) & σlnQ= σQ /Q

## Brightness Temperature 22 GHz V

- SSM/I OBSERVATIONS
- _Nearest Neighbor_ to Model Grid
**2002 12 **_**26 2154**_** UTC**

- Mesoglobal 12h FORECAST
- 800x600 grid
**Valid at 2002 12 **_**27 0000**_** UTC**

- [Tb(K)]

- Tropical Cyclone Zoe

## TROPICAL CYCLONE ZOE Valid at 2002 12 27 0000 UTC SSM/I F15: SRR

**TROPICAL CYCLONE ZOE Valid at 2002 12 27 0000 UTC SSM/I F15: ****SRR**

## TROPICAL CYCLONE ZOE Valid at 2002 12 27 0000 UTC: ln (SRR+1.0)

**TROPICAL CYCLONE ZOE Valid at 2002 12 27 0000 UTC: ****ln (SRR+1.0)**
**Assimilation of F15 SSM/I Tb**

- Ln (SRR+1.0)—**BACKGROUND**
- Kain-Fritsch + Tompkins & Janiskova 2003

- Frequency

- Frequency

- Ln (SRR+1.0)—**GEM**
- Kain-Fritsch + CONSUN

## TROPICAL CYCLONE ZOE 2002 12 27 0000UTC 

**	****	****BRIGHTNESS TEMPERATURE (K)**
- CHANNEL	     **O-P**    		**O-A **		 	**Tb obs.**
- SSM/I		Bias	SD	    Bias	       SD		N	**Error (K)**
- 19V GHz     -16.0077      21.3028    -0.810110      3.10757	1098	3.0
- 19H GHz     -29.8413      41.2874    -0.507923      6.37171	1098	6.0
- 22V GHz     -4.61540      7.12777    -0.962842      2.18700 	1098	3.0
- 37V GHz     -9.29548      16.2390     -2.95461       2.21589 	531	3.0
- 37H GHz     -14.5554      33.1771     -2.17213       4.32112  	531	6.0

**TROPICAL CYCLONE ZOE 2002 12 27 0000UTC **
**(SSM/I KFTJ** **P=12h forecast)**
**profiles ok=   97.1%**

## SRR

- 	**SSM/I Surface Rain Rate PATER CAL (mm/h)**
- 	     **O-P**		           **O-A**
- 	Bias	SD	   Bias	         SD		N
-      -1.53147      3.96483     0.749011      1.77818	1063

**SSM/I Alishouse/Petty Integrated Water Vapor  (kgm-2) ****No Precip in obs**
- 	     **O-P**		           **O-A**
- 	Bias	SD	         Bias	SD	N
-           -7.54775      5.00135     -1.22411      3.11308	192

**SRR**

**IWV**

## TROPICAL CYCLONE ZOE Valid at 2002 12 27 0000 UTC: T and Q Inc.

**TROPICAL CYCLONE ZOE Valid at 2002 12 27 0000 UTC: ****T and Q Inc.**
**Assimilation of F15 SSM/I Tb**

- Temperature increments (K)

- Specific Humidity increments (gkg-1)

- SRR

- SRR

- SRR

- SRR

- _552_

- _301_

- _143_

- _82_

- _840_

- _hPa_

## SUPER-TYPHOON MITAG 2002 03 05 1200 UTC (TMI KFJT P=12h forecast): SRR

**SUPER-TYPHOON MITAG 2002 03 05 1200 UTC (****TMI**** KFJT** **P=12h forecast): ****SRR**

## SUPER-TYPHOON MITAG 2002 03 05 1200 UTC (TMI KFJT P=12h forecast): T &  Q Inc.

******T****=1.0 K**

******T****=0.5 K**

- Temperature Inc. (K)

- Specific Humidity Inc. (gkg-1)

## SUPER-TYPHOON MITAG 2002 03 05 1200 UTC (TMI KFJT P=12h forecast): SRR

******T****=0.5 K**

******T****=1.0 K**

## CONCLUSIONS

- 1D-Var Tb developed (RTTOVSCATT –SSM/I or TMI) and functional
- Schemes of moist physics are Kain-Fritsch + CLOUDST (TJ 2003)
- Showed successful analyses results for 2 tropical cyclones: Zoe and Mitag   - Analyses draws very strongly to the observations as expected
- Larger T increments (~ 0.4-0.6 K) than those obtained at ECMWF
*-1D-Var SRR analyses experiments show T increments of*
*similar magnitude *
*-Can reduce T increments if use smaller *T

## FUTURE WORK

- Replace CLOUDST (TJ 2003) with CONSUN (sundqvist variant)
- 		so that the 1D-Var forward operator (moist physics processes)
- 		more accurately reproduces GEM modeled SRR
- Validation with TRMM radar rain flux product (14 GHz radar) possible
- Perform information content study (with simulated observations)
-      Look at
- Saturation problem of Tb w.r.t SRR
- Sampling procedure for Tb in model grid box
- Direct assimilation of Tb in the GEM-LAM 3D-Var (Fillion et al.). Implement RTTOV8.    September 2004