# Presentation: 506901

## Assimilation of Infrared and Microwave Window Channels over Land

- Benjamin Ruston and Nancy L. Baker
*In collaboration with: Drs. Fuzhong Weng, Banghua Yan, and Andrew Jones*
- NRL – Monterey
- 20 April, 2005

***Assimilation of Passive Microwave Radiances over Land: Use of the JCSDA Common Microwave Emissivity Model (MEM) in Complex Terrain Regions***

- Dissertation Defense

**Notes:**
Start by thanking the committee, especially the co-chairs

## Motivation

- - improve atmos profiling & radiance assimilation over land
- - improve the Land Surface Temperature (LST)
- - reduce rejects over desert & elevated terrain
**ISSUES**:
- - true background land emission (validation)
- - uncertainty in land surface temperature analysis
- - behavior of surface emission characteristics (scales)
- How do the emission characteristics vary ?
- 		canopy properties
- 		soil properties
- 		surface roughness effects

**Motivation**

## Milestones of the Past Year

- Began March 15, 2004
*funding began Apr??,2004*
- - Gather vegetation & soil databases (GLDAS)
- - Develop IR emissivity & single-channel LST retrieval
- - Implement MEM into NAVDAS framework
- - Perform initial 1dvar emissivity retrieval
- Combine infrared & microwave into single retrieval
- Transition 1dvar for NRL beta-testing
- - Begin examination of bias correction

## 1DVAR Retrieval

- IR single-channel LST retrieval
- retrieve emissivity statistics
**currently:**
- AMSU/A and B emissivities correlated
- HIRS/3 emissivities independent
- all retrieved simultaneously

**1DVAR Retrieval**

**1DVAR retrieval is used to handle non-linear surface sensing channels**
***1dvar preprocessor passes variables:  sfc emissivity, LST***

## Quality Control

**Quality Control**

- redevelop HIRS/3 radiance quality control using simple cloud mask

## Case Study

**Study periods:**
- Mar-Apr 2003 & 04
- Aug-Sep 2003 & 04
**Features:**
- Changing season
- UAE2 overlap
- Dust Storm Events

## Surface Emissivity

- Land Databases indexing to spectral library

**Surface Emissivity**

**How is the first guess emissivity made?**

**Microwave**:
- 1dvar retrievals create statistical database       MEM used for snow/ice & vegetation fractions > 75%

## Emissivity Means

- 1-dvar retrieval incorporates
- HIRS/3, AMSU/A and AMSU/B
- to **simultaneously** retrieve
- profiles T & q, emissivity, and LST

## Emissivity Std Deviation

- standard deviations small for ocean, highly vegetated land
- standard deviations larger for when intermittent snow/ice, coastlines

## Transmission

- infrared “window” becoming opaque in tropics
- 183.3±7 GHz emissivity retrieval often relies on cross correlations

## Future Work

- Coming Year:
- - complete CRTM implementation
- - transfer methodology to NCEP
- - mesoscale impact studies (UAE2)
-  extend to SSMI/S assimilation
-  complete strategy for bias correction
- May need some help:
- - footprint matching (beam filling)
- - land surface model (Noah implementation/Teddy Holt)

## Summary

- Dr. Nancy Baker (PI) & Benjamin Ruston (co-Investigator)
- Naval Research Laboratory, Monterey, CA
- collaborators: Drs. Fuzhong Weng, Banghua Yan, & Andrew Jones
**Purpose**:
- - Improve atmospheric profiling & radiance assimilation over land
- - Improve the Land Surface Temperature (LST)
- - Reduce rejects over desert & elevated terrain
**Milestones:**
- - Developed IR emissivity & single-channel LST retrieval
- - Implemented MEM into NAVDAS framework
- - Performed initial 1dvar emissivity retrieval
- Combined infrared & microwave sensors into a single retrieval
- Submitted working code to NRL beta-testing platform
**Future Plans:**
- - Complete CRTM implementation
- - Transfer methodology to NCEP
- - Mesoscale impact studies (UAE2)
-  Extend to SSMI/S assimilation
-  Complete strategy for bias correction

**Summary**