# Presentation: 431273

## Aqua Mission ReviewAtmospheric Infrared Sounder

**Moustafa Chahine, AIRS Science Team Leader**
**Hartmut G. Aumann, AIRS Project Scientist**
**Bjorn Lambrigtsen, AMSU Instrument Scientist**
**Steven Friedman, AIRS Project Manager (Acting)**
**August 23, 2005**
**Jet Propulsion Laboratory**
**California Institute of Technology**
**Pasadena, CA**

## http://airs.jpl.nasa.gov

**The AIRS/AMSU/HSB data will be used to address several climate questions**
**Improving weather prediction****:  ****AIRS Already Achieved 6 hours in 6 days improvement in NH with NCEP Operational Model (JCSDA)**** **
**Climate Studies:  ****Determine the distribution and variations of water vapor - Earth’s primary greenhouse gas**
**Tropospheric Minor Constituents:****  O****3****, CO****2****, CO, CH****4****, SO****2****.  **
**        *****Will provide the first satellite global map of the distribution of the tropospheric concentration of CO******2***

## AIRS – Providing High Quality Sounding Data

**AIRS provides extensive data for weather and climate analysis:**
**Daily coverage exceeds 90% of Earth’s surface and atmosphere**
**Nearly continuous coverage from August 31, 2002 forward**
**In 3+ years since launch in May 2002, AIRS continues to provide hyperspectral sounding data that is:**
**Uniquely stable **
**frequencies stable to <5 ppm**
**radiometry stable to <8mK/Y**
**Effective for studying diurnal, seasonal, annual climate trends**
**AIRS data products available to the public:**
**Calibrated Level 1B radiances available since November 2002**
**Validated Level 2 products available since September 2003**
**Validated Level 3 products available since April 2005**

## Version 4 Core Science Products

**Jan. 03 Air-Surface Temp**

**Jan.03 Tropospheric H****2****O**

**Jan. 03 Clouds**

## OPERATIONAL ACHIEVEMENTS

**AIRS has been a key weather forecasting data source for more than 2 years**
**Using JPL developed software, NOAA processes and distributes AIRS data to global numerical weather prediction centers:**
**AIRS data assimilated by:**
**NOAA/NCEP**
**ECMWF**
**UKMetOffice**
**Use of AIRS data has increased the accuracy of weather forecasting.**
**6-hour improvement in six-day weather forecasts**
**“****Normally takes several years to achieve at operational weather centers...”**
**“****This magnitude of improvement is quite significant when compared with the ****	****rate of general forecast improvement over the last decade.” **** ****	****	****	****	****	****– John Le Marshall (JCSDA)**
**Improves accuracy of positioning and intensity of Tropical Cyclone (TC) forecasts**
**“****We can say with reasonable confidence that AIRS has an important impact on TC forecasts.”****	****	****	****	****– James Cameron (UKMetOffice)**

## AIRS PUBLICATIONS

**Publications by AIRS Team (JPL and external)**
**39 publications in 2004**
**17 publications during 2005, to date**
**Special sessions on AIRS conducted at:**
**American Geophysical Union San Francisco Fall Annual Meeting,  December 2004**
**American Meteorological Society Annual Meeting, January 2005**
**American Meteorological Society Annual Meeting,  January 2006 (scheduled)**
**Submitted for publication:**
**1 article:  Bulletin of the American Meteorological Society (BAMS)**
**1 article:  Geophysical Research Letters (GRL)**
**Scheduled for publication:**
**15 papers:  special issue in Journal of Geophysical Research (JGR) on AIRS Validation (Publication date: early 2006)**

## RECENT SCIENCE ACHIEVEMENTS

**AIRS Channel Slicing Used to Depict Upper Tropospheric Moisture**
**Intense convective activity associated with a hurricane pushes water into the upper troposphere, measured by AIRS**
**The upper tropospheric water above 300 mb was measured by AIRS on Aqua**** **
**1:30 pm overpass on Saturday July 9, 2005**
**Hurricane Dennis was at its peak intensity. Note the band of elevated upper tropospheric moisture along the path of the hurricane. **

- AIRS Near IR

- AIRS Infrared Window Channel

- AMSU Channel

## RECENT SCIENCE ACHIEVEMENTS

**RECENT SCIENCE ACHIEVEMENTS**

**Total****Ozone**

**CH****4**

**SO****2**

**Aerosols**

**CO**

**MODIS**

**AIRS**

**Anatahan April 6, 2005**

*McMillan, UMBC*

*Lee, JPL*

*Irion, JPL*

*Strow, UMBC*

*Barnet, NOAA*

## SCIENCE ACHIEVEMENTS

**AIRS is well suited to study a number of processes poorly represented in numerical weather models:**
**Tracking upper tropospheric water vapor variations***(Chahine / Hearty, JPL)*** **
**Madden-Julian Oscillation ***(Tian, JPL/Caltech)*
**Cirrus Clouds ***(Kahn, JPL)*
**Recent studies with trace gases and aerosols show promising results, many of which are only available with AIRS globally:**
**CO****2**** ***(Chahine, JPL)*
**CO ***(McMillan, UMBC)*
**Silicate signatures ***(Strow, UMBC)*

## AMSU-A1 POWER BUS CURRENT SPIKES

**Current spikes detected on the AMSU-A1-2 noisy bus that powers the AMSU-A1-2 antenna**
**Spikes, first identified during May 2005, have tapered off since July 1 **
- At peak, maximum current was ~50mA, 7% over normal
- Peak current remained well below red limit of 125 mA
**Current spikes have NOT affected instrument operations**
**This specific problem:**
- Has been logged in an ISA
- Is being closely monitored
- Has been studied in detail
**There is no imminent danger to ****the AMSU-A1 instrument at this time**
**NO indication of instrument failure**
**Recommendation: maintain routine****operations, continue monitoring**
***Note: AMSU instruments onboard Aqua have ******exceeded their three-year design lifespans and******continue to perform well. AMSU instruments ******onboard other (NOAA) satellites continue to ******operate well beyond their projected lifespans.***

## AMSU-A1 POWER BUS CURRENT SPIKES

**Potential Science Impact:**
**Generation of AIRS Level 2 Products currently uses AMSU for cloud clearing**
**Continued cloud clearing can be generated solely from AIRS data**
**It is the consensus of the AIRS Science Team that AMSU remains the preferred approach for AIRS cloud-clearing**
**Potential Forecast Impact to Numerical Weather Centers:  Minimal**
**Minimal: Radiances are assimilated only, not AIRS retrievals**

## AMSU-A1 POWER BUS CURRENT SPIKES

**Current Status**
**As a contingency measure, the AIRS Project is developing a modification to the Level 2 retrieval program that will successfully operate, even with the absence of AMSU data.**
- GOAL: Complete and have upgrade available, should AMSU-A1-2 fail
- JPL expects to complete this upgrade early this fall
- Planned inclusion in Version 5 release
**As long as AMSU-A1-2 continues in NORMAL operations, utilize AIRS and AMSU data in retrieval processing**
**The GSFC DAAC, NOAA and JPL continue to utilize AMSU data in all Level 1, Level 2 and Level 3 processes**

## Aqua Mission ReviewAtmospheric Infrared Sounder

**Backup Slides - AMSU Anomaly**

## Case study: July 18, 2005 ~1800 UT

## Case study: Granules 171-189

## AMSU-A1-2 anomaly analysis

**AMSU-A1-2 anomaly analysis**

## Evidence, Hypotheses & Conclusions

**The evidence**** **
**Increased mechanical resistance ******** increased motor current**
**Cooling caused by very cold Antarctic plateau (motor temp vs. OLR)**
**Anomalous heating @ closest approach to SP (10 minute lag)**
**Current anomalies started ~ May 1; peaked ~ July 1; now rapidly declining**
**The hypothesis**** **
**Anomaly is triggered by strong radiative cooling over the Antarctic plateau during winter and brief solar heating during transition from descending to ascending (sun illuminates nadir deck)**
**Solar heating does not vary by season but radiative cooling is strongest in southern winter**
**Cooling/heating differentials may cause thermal stress on scan system**
**Thermal stress may cause increased loading on motor bearings**
**Bearings may have deteriorated and now more susceptible to thermal stress/strain**
**There may have been deterioration/loss of thermal protection systems (MLI)**
**Anomaly is expected to reappear next southern winter**
**The conclusions**** **
**No cause for concern at this time**
**Instrument science performance is not affected**
**So far no indications of a deteriorating situation**