AIRS Science Team Meeting

Agenda

Session 1: AIRS and Aqua Program Status

Moustafa Chahine - JPL - Welcome
Claire Parkinson - NASA GSFC - Aqua Program Status
Ramesh Kakar - NASA HQ - Aqua Program Status
Tom Pagano - JPL - Project Status and Science Highlights
Denis Elliott - JPL - Instrument Operations Status

Session 2: Version 5.0 Progress Overview

George Aumann - JPL - Version 5 Objectives / Level 1B
Chris Barnet - NOAA - Research Progress using AIRS Data at NOAA
Joel Susskind - GSFC - Characteristics of the Version 5 Retrieval Algorithm
Wallace McMillan - UMBC - AIRS Composition Products in Version 5
Larrabee Strow - UMBC - V5 RTA: Validation, Aerosols, and Minor Gases

Session 3: Four Years of Trends in AIRS Data

George Aumann - JPL - Climate Trends in AIRS Level 1B
Larrabee Strow - UMBC - Global CO2 Growth Rates with AIRS
Mitch Goldberg - NOAA - Generation of AIRS radiance dataset for climate studies
Joel Susskind - GSFC - 4 years of monthly mean Level 3 AIRS products
Thomas Hearty - JPL - Trends in AIRS Products

Session 4: AIRS Weather Forecast Improvement Studies

Ron Gelaro, Emily Liu, Ivanka Stajner, Michele Rienecker - GMAO - Use of AIRS in the GEOS-5 Data Assimilation System
Hong Li, Eugenia Kalnay - UMD - Progress report of local ensemble transform Kalman filter and AIRS
Will McCarty/ Gary Jedlovec - MSFC - Detection of Cloud-free Radiances in GSI and Their Impact on Short-term Weather Forecasts in WRF
Brad Zavodsky / Gary Jedlovec - MSFC - An Update on Regional Profile Assimilation and NRT Modeling Plans
Kieth Brewster/Shanna Sampson - Univ. of Oklahoma - Update on Optimal Use of AIRS Retrievals in Analyses for Short-Term Weather Forecasts
Bob Rosenberg - GSFC - Impact of assimilating AIRS retrievals on 5 day forecast using the GEOS-5 DAS

Session 5: Atmospheric Temperature and Water Vapor Products

Thomas Hearty - JPL - AIRS/AMSU and AIRS-Only Version 5 Level 2 Testing
Hengchun Ye - JPL - Antarctic WV - AIRS vs radiosondes
Eric Fetzer - JPL - AIRS/MLS Upper Tropospheric Water Vapor Comparisons
Fengying Sun - NOAA - AIRS Level 2 convective products
Lihang Zhou - NOAA - Status of the v5 cloud cleared and AIRS-only regressions
Antonia Gambacorta - NOAA - AIRS water vapor validation using the ARM CART SGP, TWP, and NSA best estimate profiles
Blackwell, William - MIT - Stochastic Cloud Clearing/Neural Network Retrieval Progress
Mike Theobald - GES/DISC - AIRS Processing at the GES DISC

Session 6: Version 6.0 Planning and Discussion

Steve Friedman - JPL - Version 6.0 Schedule
Joel Susskind - GSFC - Improved Version 5 and Suggestions for Version 6

Session 7: Atmospheric Composition Products

Bill Irion - JPL - AIRS Version 5 ozone retrievals
Eric Maddy - NOAA - AIRS averaging functions
Murty Divarkarla - NOAA - Ozone validation using the WOUDC ozonesondes
Laura Pan - NCAR - Dynamical variability of ozone near tropopause from AIRS data
Baijun Tian - JPL - MJO analysis of O3 based on AIRS and TOMS
Chahine/Olsen/Chen - JPL - VPD Mid-Tropospheric O3 and CO2
S. Hannon /L. Strow - UMBC - Retrievals of SO2 and HNO3
Wallace McMillan - UMBC - New CO science from INTEX-B
Jennifer Wei - NOAA - AIRS CO & Ozone Correlations in Biomass Regions
Xiaozhen Xiong - NOAA - Status of AIRS methane retrieval

Session 8: Cloud and Aerosol Products

Michael King - GSFC - MODIS Atmosphere Products
S. DeSouza-Machado /L. Strow - UMBC - Progress studying duststorms and effects on AIRS retrievals
Brian Kahn - JPL - Cloud properties from AIRS: Cirrus and initial comparisons to Cloudsat
Nick Nalli - NOAA - AMMA-AEROSE-II Cruise Summary

Session 9: Surface Temperature and Emissivity

Evan Fishbein - JPL - A comparison of calculated and cloud-cleared radiances over land and water
Bob Knuteson - UW - Validation of AIRS land surface products

Session 10: Product Accuracy and Validation

Jim Yoe - NOAA - Comparison of GPS and AIRS TPW
Aumann/Broberg/Gregorich - JPL - Comparison of AIRS, MODIS & HIRS L1B over Antarctica
S. Hannon/L. Strow - JPL - Improvements to AIRS Spectral Calibration
Denis Elliott - JPL - AIRS Spatial Response Functions in Orbit
Haibing Sun - JPL - MODIS IR Channel Spectral Response Function Calibration with Co-located AIRS Observations
Dave Whiteman - JPL - Satellite validation activities from the Howard University Research Campus in Beltsville, MD
Ed Olsen - JPL - AIRS Version 5.0 User Guide and Documentation

MEETING SUMMARY

written by Tom Pagano, AIRS Project Mangager and George Aumann AIRS Project Scientist

Thomas S. Pagano, AIRS Project Manager, Jet Propulsion Laboratory
Hartmut "George" H. Aumann, AIRS Project Scientist, Jet Propulsion Laboratory

The Fall 2007 Atmospheric Infrared Sounder (AIRS) Science Team Meeting was held at the Greenbelt Marriott on September 26-29, 2006. The AIRS Science Team Leader, Mous Chahine, welcomed the crowd of approximately 80 guests and shared the motto for AIRS during the build of the instrument: "Always Make Progress". Mous showed data presented in the July 2006 BAMS article "AIRS Improving Weather Forecasting and Providing New Data on Greenhouse Gases" where he breaks down the errors for the near-surface retrieved temperature profile. The result shows a cloud clearing error of 0.6K, a co-location error (with radiosondes) of 0.8K, and a surface emissivity of 0.9K. His message is that the next version of AIRS should focus on improving the surface emissivity retrieval. Mous expressed his delight for the progress made by the AIRS Science Team and the user community using AIRS data.

Claire Parkinson, the Aqua Project Scientist, gave a status of the Aqua Project. The Earth Science Reference Handbook is now published. The Aqua spacecraft is doing well, but recently terminated a sequence of orbital inclination adjust maneuvers after experiencing unexpected responses in the semi-major axis. Claire said that, in terms of fuel, the Aqua mission could probably continue to operate through 2015. However, funding for continuation of the mission will depend on next year's Senior Review. Finally, Claire went through the ten Aqua mission success criteria, in each case showing how the mission is doing so far in terms of meeting them. Of the ten, at this point six have been completed. The AIRS has two of the ten criteria and will satisfy these with validation of the temperature profiles in the Polar Regions with the Version 5 release (now expected in January 2007).

Ramesh Kakar, the NASA Program Scientist for Aqua, said he is "continually amazed by the results" from the AIRS team and that AIRS "continues to set standards for IR radiometry". He expressed his thanks to the team and asked to "keep the results coming". Ramesh mentioned the efforts by NASA Headquarters to review the current selection of proposals in the EOS re-compete and was aware of the critical need to make selections as soon as possible. The Senior Review of the Aqua platform is expected to take place in April 2007 along with the review of Terra and TRMM. At this time the AIRS Team Leader Proposal will also be due.

Bruce Doddridge, the NASA Program Manager for Tropospheric Chemistry expressed his thanks for the "amazing level of support for the INTEX-B" campaign. The AIRS played an important role in this campaign, with Wallace McMillan providing the AIRS analysis for the team.

Tom Pagano, the AIRS Project Manager, presented science highlights from the last AIRS Science Team meeting and highlighted recent publications by AIRS users. Tom congratulated recent NASA Award Recipients for their work related to AIRS including Ramesh Kakar who received an Exceptional Service Medal, John LeMarshal of the JCSDA who received an Exceptional Scientific Achievement Medal, Annmarie Eldering of JPL who received an Exceptional Achievement Medal, and BAE Systems who received a Public Service Group Achievement Award for their development of the AIRS instrument. Finally, Tom presented a new mission concept called ARIES designed to meet the future requirements of AIRS and MODIS in a single instrument.

Denis Elliott, the AIRS Project Operations and Calibration Lead, said the AIRS and AMSU instruments are operating well with all currents, voltages and temperatures as expected. The only anomaly worth mentioning is an increase of noise in one detector per month beyond the threshold limits, mostly due to radiation effects in orbit.

George Aumann, the AIRS Project Scientist, JPL, presented the objectives of Version 5, and showed how we have met the vast majority of objectives defined for version 5 in 2004. The most significant improvements are the addition of three new products including the upper tropospheric ozone profile, Carbon Monoxide and Carbon Dioxide.

Chris Barnet, NOAA, presented the numerous activities happening at NOAA. Chris' group provides real time support to a wide range of flight and validation campaigns requiring AIRS data. Chris is also providing data for assimilation studies (Li/Kalnay). NOAA also does their own validation of AIRS data. Finally, NOAA is actively involved in the development of the AIRS Level 2 retrieval including providing regression parameters for surface emissivity and cloud clearing and development of the trace gas retrieval products. Tom Pagano expressed his thanks on behalf or NASA for the considerable contribution by NOAA and Chris' team to the AIRS project.

Joel Susskind, GSFC, showed the improvement in yield and accuracy of the atmospheric and surface temperatures and water vapor products in Version 5. Wallace McMillan, UMBC, showed the addition of CO, CH4 and Ozone profile in Version 5. Wallace said the products include averaging kernels which are a big improvement over the development products examined earlier. In particular the AIRS CO product is as close to the MOPITT product as could possibly be made. Larrabee Strow, also of UMBC, presented the progress in the RTA for AIRS that includes a correction to the frequencies of the AIRS M12 module, and the inclusion of the ability to vary CO2, N2O, SO2, and HNO3. The RTA has also been corrected for Non-LTE effects.

Tuesday afternoon was dedicated to trends in the AIRS data since launch in an effort to determine the ability of AIRS to detect global climate signatures. The first speaker, George Aumann, JPL, showed that the AIRS radiances are stable at about 10mK/year which qualifies it for being suitable for observing small changes in climate signatures. Larrabee Strow, UMBC, showed the stability of AIRS is sufficient to accurately detect the seasonal variations and annual global rise in CO2. Mitch Goldberg, NOAA, shared his limb adjusted radiance products for evaluation of climate forcing, feedback, and response. Joel Susskind, GSFC, showed trends in the Version 4 Level 3 products that are consistent with other satellite products (e.g. TOVS). These trends include the El-Nino of 2003 and La-Nina of 2006. Thomas Hearty, JPL, showed a small trend (0.1K/year) in boundary layer air temperature that has steadily increased over the mission and is not reflected in the ECMWF forecast. There is no explanation for the observed trend in AIRS data at this time.

The Wednesday morning session was dedicated to assimilation studies using AIRS data. Ron Gelaro of the GSFC/GMAO presented results from assimilation of the AIRS temperature and water vapor channels into the GEOS-5 data assimilation system. The AIRS provides the largest number of observations of all the space instruments assimilated. A net positive impact is seen from the assimilation of AIRS radiances, but further work is required to realize benefit in the water vapor and ozone channels.

Hong Li and Eugenia Kalnay, University of Maryland, showed consistent positive forecast impact in both the SH and the NH by assimilation of AIRS temperature retrievals into the 4D-Local Ensemble Transform Kalman Filter. The LETKF has been shown to be much more accurate than 3D-Var (PSAS and SSI) and able to efficiently assimilate large numbers of observations. The 4D extension allows the assimilation of satellite data at the right observation time. Will McCarty of the University of Alabama, Huntsville used a method for cloud detection for assimilation of radiances into the regional weather forecasts. Brad Zavodsky also with the University of Alabama, Huntsville showed an overall positive impact of the temperature and moisture fields with the inclusion of AIRS profiles. During a case study, the AIRS data improved the 53 hour forecast by showing a 4 mb decrease in pressure in the region of the storm as well as improvement in prediction of total rainfall. Shanna Sampson of the University of Oklahoma determined the AIRS filter parameters needed to smooth the comparison data; this resulted in significant improvement in the comparison. The final talk on assimilation was by Bob Rosenberg of GSFC. By assimilation of AIRS temperature profiles into the GEOS-5 data assimilation system he showed approximately a 6 hour average improvement in skill over 26 5-day forecasts in the Northern Hemisphere extra-tropics.

Wednesday afternoon had several sessions addressing the quality of the AIRS retrievals. Thomas Hearty, JPL, began with comparisons of the AIRS Version 4 and Version 5 retrievals indicating an increase in yield and accuracy near the surface, and a possible reduction in the dry bias in the upper troposphere. Hengchun Ye, Cal State LA, gave the first look into the performance of the AIRS total precipitable water in the Polar Regions. Results show AIRS compares well with radiosondes and ECMWF. Eric Fetzer, JPL, showed comparisons of AIRS and MLS water vapor in the upper troposphere. Results show agreement to a few percent at 250 mb where we expect both the MLS and AIRS to have common sensitivity. Above this the AIRS looses sensitivity, and below this, the MLS shows a dry bias.Fengying Sun, NOAA, showed the value of convective products (e.g. CAPE) and recommended we produce these products for AIRS. Lihang Zhou (NOAA) presented her results of generating regression coefficients for the AIRS Version 5 system. A major part of this was updating the surface emissivity training set. Her efforts also produced a very good regression solution for the AIRS-only (no AMSU) backup retrieval system. Antonia Gambacorta, of UMBC, examined the effects of spatial gradients when comparing AIRS to radiosondes, and concluded we need to restrict radiosondes to within 50 km of the AIRS retrievals. Working with the retrieval, she also realized that the retrieval may be over damped in its present configuration. Bill Blackwell, MIT LL, presented recent progress in stochastic cloud clearing and a neural network retrieval algorithm. His temperature retrievals compared better with ECMWF than the AIRS retrieval system.

After the break, Mike Theobald of the GES/DISC gave a status of the processing currently being performed at the GES/DISC in support of AIRS. The GES/DISC is moving towards Linux clusters and expect to be able to process AIRS data at 10x (10 days of AIRS data in 1 day). Mike also announced that the GES/DISC now is processing AIRS data in real time (for limited distribution, and with predicted ephemeris). The support of the GES/DISC of the AIRS Project has been "phenomenal" since the start of AIRS operations, in particular, their user services, development of online applications, processing and distribution.

Steve Friedman led the session on planned improvements for Version 6. He showed the current delivery schedule for Version 5 and a plan for Version 6. Steve was followed by Joel Susskind who presented performance of the AIRS-Only retrieval system and had suggestions for version 6 including improving surface parameter retrieval and a higher spatial resolution product. Chris Barnet suggested several improvements including removing biases, better use of the microwave, and implementation of new trace gas products among others. Larrabee Strow also suggested including new trace gas products and aerosols in Version 6, but also suggested a "Level 1C" to provide radiances on a fixed frequency set for climate users.

Thursday morning was dedicated to the evaluation of the composition products from AIRS. Eric Maddy, NOAA, presented the averaging kernels for version 5. They represent a major improvement over prior versions, and when used properly, he showed how they improve comparisons with sondes. Bill Irion, JPL, presented the differences in the Version 4 and Version 5 ozone product. Version 5 reduces biases, but still has difficulty in regions with less than 100 ppbv of ozone. The retrieval appears to be "over damped" indicating that the information content is there, but we need to relax the retrieval somewhat.Murty Divakarla, NOAA, presented comparisons of AIRS retrievals with ozonesondes and shows the information content in AIRS is better than ECMWF, but AIRS shows biases below 200 mb, but does well above this. Laura Pan, NCAR, showed comparison of AIRS ozone with radiosondes and aircraft observations. She also sees the bias in AIRS data below 200mb, but indicates the AIRS shows good sensitivity in the 70-250 mb region. AIRS data in its current form shows tremendous value in studying the Stratospheric Tropospheric Exchange (STE). Baijun Tian, JPL, presented results from a study of the intraseasonal variations of the tropical total ozone using AIRS and TOMS data. His findings show that there is a clear Madden-Julian Oscillation (MJO) in the tropical total ozone. The maxima of the total ozone MJO anomalies are located over the subtropics and are dynamically driven by the size and magnitude of subtropical cyclones or anticyclones associated with the equatorial MJO convection.

After the morning break, Mous Chahine, JPL AIRS Science Team Leader, presented beta retrievals of mid tropospheric CO2 using the method of Vanishing Partial Derivatives. The results show good comparison with models in the mid latitudes, but a significant difference in the southern hemisphere. The ESA SCHIAMACHY shows a similar result to AIRS. Modelers at CalTech and JPL are working with Mous to understand the differences. Scott Hannon, UMBC, presented first results of his SO2 and HNO3 retrievals from AIRS. The sensitivity of AIRS to SO2 is 1 Dobson Unit which makes it primarily useful for high concentrations such as volcanoes. AIRS sensitivity to HNO3 is similar to SO2, except sensitivity to HNO3 may be higher in the lower troposphere.

Wallace McMillan, UMBC, presented results of validation of AIRS Carbon Monoxide. AIRS CO and O3 were used in the TEXas Air Quality Study (TEXAQS) - II to support flight planning. The AIRS data when combined with modeled data are useful for predicting regional air quality. For example, fires in Louisiana were found to be contributing to air quality of Houston. The integration of AIRS O3, CO and H2O were helpful in understanding the accuracies of the retrieved individual quantities. Jennifer Wei, NOAA, showed how AIRS captures stratospheric intrusions from tropospheric folds (similar to Laura Pan). Her analysis of the retrieval indicates that the physical retrieval can be improved with the addition of more AIRS ozone channels, and the reduction in the amount of damping. Xiaochen Xiong, NOAA, presented some of the first results from the AIRS CH4 retrieval. His results show good agreement with aircraft and models, and was able to see an increase in CH4 over the Canada and the Tibetan plateau in summer.

The afternoon session began with an invited presentation by Michael King, GSFC, on the atmosphere products from MODIS. MODIS has a superb atmospheric products including cloud, aerosol and water vapor products. His presentation was especially appreciated and stimulated dialogue amongst team members on how to use MODIS more effectively. The following talk by Sergio DeSouza-Machado, UMBC, compared transmittance in dust regions from AIRS and MODIS and gets very good agreement. The AIRS Outgoing Longwave Radiation (OLR) shows correlation with the AIRS dust score. Brian Kahn, JPL, presented results from examining AIRS cirrus particle size compared to in-situ and MODIS. The AIRS cloud top heights also compare well with CloudSat.

Nick Nalli, NOAA, shared his exciting venture on board the NOAA ship, the Ronald H. Brown as part of the AEROS campaign. The cruise covered periods of May through July, 2006 in the central Atlantic Ocean. The primary mission was to place 2 ocean moorings, but numerous radiosonde, ozonesonde, smoke, dust and surface observations were made along the way. Evan Fishbein, JPL, presented his evaluation of the AIRS cloud cleared radiances compared to ECMWF and emissivities, comparing them to models. Bob Knuteson, UW, compared the land surface temperature retrievals from AIRS to observations at the ARM Southern Great Planes Central Facility. Results compare well with a 1K bias at night. Surface emissivity was also examined but as expected needs more work.

Friday morning concluded the meeting with validation and calibration of AIRS. Jim Yoe, NOAA, showed "remarkable" agreement between AIRS and GPS total water vapor measurements. George Aumann, JPL, compared AIRS, MODIS and HIRS radiances over Antarctica with good precision. Larrabee Strowshowed the spectral stability of AIRS to be about 6 ppm over the life of the mission (the rate is decreasing significantly with time), but believes in order to see climate signatures, even this small amount needs to be accounted for. Denis Elliott, JPL, presented a technique to use the AIRS pre-flight spatial response measurements to overlay MODIS and AIRS radiances to better than 1K (1 sigma) in non-uniform scenes.Haibing Sun, NOAA, also showed improvement using a simulated spatial response function and that AIRS can be used to determine the Aqua/MODIS spectral response functions in orbit. Dave Whiteman, GSFC, presented results from WAVES 2006, which involved validating AIRS using raman lidar, radiosondes and ozonesondes. Finally Ed Olsen, JPL, discussed plans for providing a user guide for the AIRS Version 5 delivery.

The AIRS Science Team Meeting was a tremendous success with over 50 presentations by government and universities. Presenters shared their hard work developing and validating the numerous products from AIRS with almost all results favorable. The AIRS experiment is a paving new territory for high spectral resolution infrared observations of the earth in support of NASA global earth science, climate, and weather forecasting. The next team meeting is scheduled for March 6 - 9, 2007, at CalTech in Pasadena, CA, and will focus on the scientific discoveries being made with AIRS data.