This paper discusses the performance of AIRS and examines how it is meeting its operational and research objectives based on the experience of more than 2 yr with AIRS data. We describe the science background and the performance of AIRS in terms of the accuracy and stability of its observed spectral radiances. We examine the validation of the retrieved temperature and water vapor profiles against collocated operational radiosondes, and then we assess the impact thereof on numerical weather forecasting of the assimilation of the AIRS spectra and the retrieved temperature. We close the paper with a discussion on the retrieval of several minor tropospheric constituents from AIRS spectra.

AIRS: Improving Weather Forecasting and Providing New Data on Greenhouse Gases.

A poor validation strategy will compromise the quality of satellite-derived sea surface temperature (SST) products because confidence limits cannot be quantified. This paper addresses the question of how to provide the best operational strategy to validate satellite-derived skin sea surface temperature (SST skin) measurements. High quality in situ observations obtained using different state-of-the-art infrared radiometer systems are used to characterize the relationship between the SST skin, the subsurface SST at depth (SSTdepth), and the surface wind speed. Data are presented for different oceans and seasons. These data indicate that above a wind speed of approximatel y6ms 21 the relationship between the SSTskin and SSTdepth, is well characterized for both day- and nighttime conditions by a cool bias of 20.17 6 0.07 K rms. At lower wind speeds, stratification of the upperocean layers during the day may complicate the relationship, while at night a cooler skin is normally observed. Based on these observations, a long-term global satellite SST skin validation strategy is proposed. Emphasis is placed on the use of autonomous, ship-of-opportunity radiometer systems for areas characterized by prevailing low‐wind speed conditions. For areas characterized by higher wind speed regimes, well-calibrated, qualitycontrolled, ship and buoy SSTdepth observations, corrected for a cool skin bias, should also be used. It is foreseen that SSTdepth data will provide the majority of in situ validation data required for operational satellite SST validation. We test the strategy using SSTskin observations from the Along Track Scanning Radiometer, which are shown to be accurate to approximately 0.2 K in the tropical Pacific Ocean, and using measurements from the Advanced Very High Resolution Radiometer. We note that this strategy provides for robust retrospective calibration and validation of satellite SST data and a means to compare and compile in a meaningful and consistent fashion similar datasets. A better understanding of the spatial and temporal variability of thermal stratification of the upper-ocean layers during low‐wind speed conditions is fundamental to improvements in SST validation and development of multisensor satellite SST products.

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Toward Improved Validation of Satellite Sea Surface Skin Temperature Measurements for Climate Research

To predict reliably what increased greenhouse gases will do to global climate, we have to understand the crucial role of clouds.

https://physicstoday.scitation.org/doi/pdf/10.1063/1.1554135

The Atmospheric Radiation Measurement Program

IN view of the interest attaching to the vaporisation and diffusion of solids, the following observations may be worthy of record.

The Diffusion of Solids

Uncertainties in projections of future climate change have not lessened substantially in past decades. Both models and observations yield broad probability distributions for long-term increases in global mean temperature expected from the doubling of atmospheric carbon dioxide, with small but finite probabilities of very large increases. We show that the shape of these probability distributions is an inevitable and general consequence of the nature of the climate system, and we derive a simple analytic form for the shape that fits recent published distributions very well. We show that the breadth of the distribution and, in particular, the probability of large temperature increases are relatively insensitive to decreases in uncertainties associated with the underlying climate processes.

Why is climate sensitivity so unpredictable

A summary of the development and recent advancements of the On-Orbit Absolute Radiance Standard at the University of Wisconsin Space Science and Engineering Center. This work is funded under the NASA Instrument Incubator Program.

On-Orbit Absolute Radiance Standard for Future IR Remote Sensing Instruments - Overview of Recent Technology Advancements

The Submillimeter-wave and Infrared Ice Cloud Experiment (SIRICE) concept would provide global measurements of ice water path (IWP - the vertically integrated mass of ice particles per unit area), and weighted mean mass particle diameter (Dme). The SIRICE payload consists of two instruments, the Sub-millimeter/Millimeter (SM4) Radiometer, and the Infrared Cloud Ice Radiometer (IRCIR). IRCIR is a compact, low-cost, multi-spectral, wide field of view pushbroom infrared imaging radiometer. IRCIR will employ four IR sensor assemblies to produce 90° cross-track (contiguous along-track) coverage in three spectral bands with a spatial resolution of 0.6 km at nadir. Each IR sensor assembly consists of an uncooled microbolometer focal plane array (FPA), associated sensor core electronics, a stripe filter fixed at the FPA, and an IR lens assembly. A single scene mirror is used to provide two Earth view angles, as well as calibration views of space and the on-board calibration blackbody. The two Earth view angles will be used for stereo cloud height retrievals.

The infrared cloud ice radiometer (IRCIR)

An on-orbit absolute radiance standard (OARS) traceable to SI standards on-orbit has been developed to provide end-to-end calibration verification of high accuracy IR spectral radiance measurements, to better than 0.1K brightness temperature error.

Laboratory Results From an On-Orbit Absolute Radiance Standard (OARS)

The University of Wisconsin-Madison Scanning High-resolution Interferometer Sounder (S-HIS) made high altitude observations coincident with the NASA Aqua satellite during two validation campaigns ADRIEX and EAQUATE in Italy and the United Kingdom during September 2004.

Scanning High-resolution Interferometer Sounder (S-HIS) Observations During ADRIEX/EAQUATE

High spectral resolution observations of downwelling emission from 3 to l9 microns have been made by the Atmospheric Emitted Radiance Interferometer (AERI) Prototype at the Southern Great Plains (SGP) Cloud and Radiative Testbed (CART) site for over two years The spectral data set from AERI provides a basis for improving clear sky radiative transfer; determining the radiative impact of clouds, including the derivation of cloud radiative properties; defining the influences of aerosols in The AERI Prototype was first brought to CART in March the window regions; and retrieving boundary layer state properties, including temperature, water vapor, and other trace gases The data stream of radiometrically and spectrally calibrated radiances is routinely provided by Pacific Northwest Laboratory (PNL) to those science teams requesting it, and further information on the instrument and data characteristics is available in the ARM Science Team proceedings for 1993 and 1994 (Revercomb et al; Smith et al) and in several conference publications (Revercomb et al 1993a,b, 1994; Smith et al 1993)

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Fred A. Best

Papers

On-Orbit Absolute Radiance Standard for Future IR Remote Sensing Instruments - Overview of Recent Technology Advancements

The infrared cloud ice radiometer (IRCIR)

Laboratory Results From an On-Orbit Absolute Radiance Standard (OARS)

Scanning High-resolution Interferometer Sounder (S-HIS) Observations During ADRIEX/EAQUATE

Atmospheric emitted radiance interferometer (AERI): Status and the aerosol explanation for extra window region emissions