Eric Maddy

Daily global maps of carbon monoxide from NASA's Atmospheric Infrared Sounder

Received 24 October 2004; revised 19 January 2005; accepted 4 March 2005; published 1 June 2005. [1] We present the first observations of tropospheric carbon monoxide (CO) by the Atmospheric Infrared Sounder (AIRS) onboard NASA’s Aqua satellite. AIRS daily coverage of 70% of the planet represents a significant evolutionary advance in satellite trace gas remote sensing. Tropospheric CO abundances are retrieved from AIRS 4.55 mm spectral region using the full AIRS retrieval algorithm run in a research mode. The presented AIRS daily global CO maps from 22– 29 September 2002 show large-scale, long-range transport of CO from anthropogenic and natural sources, most notably from biomass burning. The sequence of daily maps reveal CO advection from Brazil to the South Atlantic in qualitative agreement with previous observations. Forward trajectory analysis confirms this scenario and indicates much longer range transport into the southern Indian Ocean. Preliminary comparisons to in situ aircraft profiles indicate AIRS CO retrievals are approaching the 15% accuracy target set by pre-launch simulations. Citation: McMillan, W. W., C. Barnet, L. Strow, M. T. Chahine, M. L. McCourt, J. X. Warner, P. C. Novelli, S. Korontzi, E. S. Maddy, and S. Datta (2005), Daily global maps of carbon monoxide from NASA’s Atmospheric Infrared Sounder, Geophys. Res. Lett., 32, L11801, doi:10.1029/ 2004GL021821.

Vertical Resolution Estimates in Version 5 of AIRS Operational Retrievals

In this paper, we present an overview of averaging-kernel computations from the Atmospheric Infrared Sounder (AIRS) Version 5 product retrieval software. Temperature and moisture retrievals form the focus of this paper; however, some results for all other retrieved gas amounts are presented. The theory and methodology required to utilize the averaging kernels for comparison of AIRS retrievals with correlative measurements are given. The averaging kernels are used to transform correlative measurements to AIRS effective resolution and are used to assess and derive the vertical resolution of Version 5 temperature and moisture retrievals in different atmospheric conditions. We find that depending on the scene, AIRS Version 5 tropospheric temperature (moisture) retrieval resolution, which is as determined by the full-width at half-maximum of the averaging kernels, ranges between 2.5 km (2.7 km) near the surface and 7.1 km (4.3 km) near the tropopause.

A comparison of satellite tropospheric carbon monoxide measurements from AIRS and MOPITT during INTEX‐A

Received 16 August 2006; revised 17 November 2006; accepted 28 February 2007; published 9 June 2007. [1] Satellite CO measurements from Measurements of Pollution in the Troposphere (MOPITT) and Atmospheric Infrared Sounder (AIRS) were used in the Intercontinental Chemical Transport Experiment–North America (INTEX-A) by the flight planning team to monitor local emissions and the transport of polluted air masses. Because simultaneous measurements of tropospheric CO from both AIRS and MOPITT were used by different investigators during this experiment, a cross reference and comparison are necessary to understand these two data sets and their impacts to the scientific conclusions developed from them. The global CO mixing ratios at 500 mbar, as well as the CO total column amount, are compared between the two instruments for both direct comparison and the comparison using the same a priori profile for the period from 15 June to 14 August 2004. Also presented are the comparisons of the remotely sensed profiles by AIRS, MOPITT, and the in situ profiles collected by the DACOM. In summary, both sensors agree very well on the horizontal distributions of CO represented by the high correlation coefficients (0.7–0.98), and they agree on the CO concentrations to within an average of 10–15 ppbv. Over land, the CO variability is higher, and the correlations between the two data sets are relatively lower than over ocean; however, there is no evidence of a systematic bias. Over the oceans where the CO concentration is smaller in the lower atmosphere, AIRS-MOPITT show a positive bias of 15–20 ppbv and the details are presented.

CO2 retrievals from the Atmospheric Infrared Sounder: Methodology and validation

In this paper we describe the methodology of an offline retrieval of CO 2 from AIRS data and show comparisons of these retrievals with all available NOAA ESRL/GMD aircraft data during 2005. In general, we find that when compared to the aircraft the AIRS CO 2 estimates agree to approximately ±0.5% in middle-tropospheric CO 2 column abundances between ±65 degrees latitude.

Validating the AIRS Version 5 CO Retrieval With DACOM In Situ Measurements During INTEX-A and -B

Herein we provide a description of the atmospheric infrared sounder (AIRS) version 5 (v5) carbon monoxide (CO) retrieval algorithm and its validation with the DACOM in situ measurements during the INTEX-A and -B campaigns. All standard and support products in the AIRS v5 CO retrieval algorithm are documented. Building on prior publications, we describe the convolution of in situ measurements with the AIRS v5 CO averaging kernel and first-guess CO profile as required for proper validation. Validation is accomplished through comparison of AIRS CO retrievals with convolved in situ CO profiles acquired during the NASA Intercontinental Chemical Transport Experiments (INTEX) in 2004 and 2006. From 143 profiles in the northern mid-latitudes during these two experiments, we find AIRS v5 CO retrievals are biased high by 6%-10% between 900 and 300 hPa with a root-mean-square error of 8%-12%. No significant differences were found between validation using spiral profiles coincident with AIRS overpasses and in-transit profiles under the satellite track but up to 13 h off in time. Similarly, no significant differences in validation results were found for ocean versus land, day versus night, or with respect to retrieved cloud top pressure or cloud fraction.

Emissivity and reflection model for calculating unpolarized isotropic water surface-leaving radiance in the infrared. 2: Validation using Fourier transform spectrometers

The surface-leaving radiance model developed in Part I [Appl. Opt.47,3701 (2008)] is validated against an exhaustive set of Fourier transform spectrometer field observations acquired at sea. Unlike prior limited studies, these data include varying all-sky atmospheric conditions (clear, cloudy, and dusty), with regional samples from the tropics, mid-latitudes, and high latitudes. Our analyses show the model to have reduced bias over standard models at emission angles > or = 45 degrees.

The CrIMSS EDR Algorithm: Characterization, Optimization, and Validation

The Cross-track Infrared Sounder (CrIS) and the Advanced Technology Microwave Sounder (ATMS) instruments aboard the Suomi National Polar-orbiting Partnership satellite provide high-quality hyperspectral infrared and microwave observations to retrieve atmospheric vertical temperature and moisture profiles (AVTP and AVMP) and many other environmental data records (EDRs). The official CrIS and ATMS EDR algorithm, together called the Cross-track Infrared and Microwave Sounding Suite (CrIMSS), produces EDR products on an operational basis through the interface data processing segment. The CrIMSS algorithm group is to assess and ensure that operational EDRs meet beta and provisional maturity requirements and are ready for stages 1–3 validations. This paper presents a summary of algorithm optimization efforts, as well as characterization and validation of the AVTP and AVMP products using the European Centre for Medium-Range Weather Forecasts (ECMWF) analysis, the Atmospheric Infrared Sounder (AIRS) retrievals, and conventional and dedicated radiosonde observations. The global root-mean-square (RMS) differences between the CrIMSS products and the ECMWF show that the AVTP is meeting the requirements for layers 30–300 hPa (1.53 K versus 1.5 K) and 300–700 hPa (1.28 K versus 1.5 K). Slightly higher RMS difference for the 700 hPa-surface layer (1.78 K versus 1.6 K) is attributable to land and polar profiles. The AVMP product is within the requirements for 300–600 hPa (26.8% versus 35%) and is close in meeting the requirements for 600 hPa-surface (25.3% versus 20%). After just one year of maturity, the CrIMSS EDR products are quite comparable to the AIRS heritage algorithm products and show readiness for stages 1–3 validations.

Seven Years' Observation of Mid-Upper Tropospheric Methane from Atmospheric Infrared Sounder

NASA/Jet Propulsion Laboratory, Pasadena, CA, USA; E-Mail: Thomas.s.pagano@jpl.nasa.gov * Author to whom correspondence should be addressed; E-Mail: Xiaozhen.xiong@noaa.gov; Tel.: +1-301-316-5020; Fax: +1-301-238-2398. Received: 20 September 2010; in revised form: 28 October 2010 / Accepted: 5 November 2010 / Published: 9 November 2010 Abstract: The Atmospheric Infrared Sounder (AIRS) on EOS/Aqua platform provides a measurement of global methane (CH

Using MetOp-A AVHRR Clear-Sky Measurements to Cloud-Clear MetOp-A IASI Column Radiances

AbstractHigh spatial resolution measurements from the Advanced Very High Resolution Radiometer (AVHRR) on the Meteorological Operation (MetOp)-A satellite that are collocated to the footprints from the Infrared Atmospheric Sounding Interferometer (IASI) on the satellite are exploited to improve and quality control cloud-cleared radiances obtained from the IASI. For a partial set of mostly ocean MetOp-A orbits collected on 3 October 2010 for latitudes between 70°S and 75°N, these cloud-cleared radiances and clear-sky subpixel AVHRR measurements within the IASI footprint agree to better than 0.25-K root-mean-squared difference for AVHRR window channels with almost zero bias. For the same dataset, surface skin temperatures retrieved using the combined AVHRR, IASI, and Advanced Microwave Sounding Unit (AMSU) cloud-clearing algorithm match well with ECMWF model surface skin temperatures over ocean, yielding total uncertainties ≤1.2 K for scenes with up to 97% cloudiness.

An Experiment Using High Spectral Resolution CrIS Measurements for Atmospheric Trace Gases: Carbon Monoxide Retrieval Impact Study

We perform a demonstration experiment using the National Oceanic Atmospheric Administration Unique Cross-track Infrared Sounder (CrIS)/Advanced Technology Microwave Sounder Processing System to assess the improvement on trace gas retrievals upon switching to high spectral resolution CrIS radiance measurements (0.625 cm-1). The focus of this study is carbon monoxide retrievals. The experimental high spectral resolution CO retrievals show a remarkable improvement, of almost up to one order of magnitude in the degree of freedom of the signal, with respect to the low-resolution mode. Furthermore, high-resolution CO retrievals show similar skill with respect to existing CO operational products from the Atmospheric InfraRed Sounder, Atmospheric Sounder Interferometer, and Measurements of Pollution In The Troposphere instruments, both in terms of spatial variability and degrees of freedom. The results of this research provide evidence to support the need for high spectral resolution CrIS measurements. This is a fundamental prerequisite in guaranteeing continuity to the CO afternoon orbit monitoring as part of a multisatellite uniformly integrated long-term data record of atmospheric trace gases.