http://www.majidkiavarz.com/files/Satellite-derived%20land%20surface%20temperature%20Current%20status%20and%20perspectives.pdf

Satellite-derived land surface temperature: Current status and perspectives

A brief outline of the basic concepts of cloud filtering and atmospheric attenuation corrections used in the Multi-channel Sea Surface Temperature (MCSST) method is given The operational MCSST procedures and products are described in detail The comparative performance of AVHRR-based MCSST'S is discussed via the use of the results of the JPL Satellite-Derived Sea Surface Temperature workshops For the four data periods there is surprisingly good correspondence in the sign and location of the major monthly mean SST anomaly features derived from MCSST's and those from a screened set of ship-based SST's With the partial exception of the one data period severely affected in some areas by volcanic aerosol from El Chichon eruptions, global statistical measures of the MCSST anomalies relative to the the ship data are as follows: biases, 03–04°C (MCSST lower than ship); standard deviations, 05–06°C; and cross-correlations, +03 to +07 A refined technique in use with NOAA 9 data in 1985 has yielded consistent biases and rms differences near −01°C and 05°C, respectively

Comparative performance of AVHRR‐based multichannel sea surface temperatures

To obtain accurate estimates of surface and cloud parameters from satellite radiance data a scheme has to be devised which identifies cloud-free and cloud-filled pixels (i.e. fields of view). Such a scheme has been developed for application to high resolution (1·1 km pixel) images recorded over Western Europe and the North Atlantic by the AVHRR on the TIROS-N/NOAA polar orbiters. The scheme consists of five daytime or five night-time tests applied to each individual pixel to determine whether that pixel is cloud-free, partly cloudy or cloud-filled. The pixel is only identified as cloud-free or cloud-filled if it passes all the tests to identify that condition; otherwise it is assumed to be partly cloudy. Surface parameters (e.g. skin temperature, reflectance, vegetation index, snow cover) can then be inferred from the cloud-free radiances, and cloud parameters (e.g. cloud top temperature, optical depth and liquid water content) from the cloud-filled radiances. Only fractional cloud cover is deriv...

https://www.tandfonline.com/doi/pdf/10.1080/01431168808954841

An improved method for detecting clear sky and cloudy radiances from AVHRR data

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.

/pdf/toward-improved-validation-of-satellite-sea-surface-skin-4c3eslvrbb.pdf

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

The Global Monitoring for Environment and Security (GMES) Sentinel-3 mission

The accuracy with which sea surface temperature (s.s.t.) can be measured using satellite infrared radiometers is limited primarily by uncertainties in the correction for atmospheric effects upon the measured radiance. This paper reports an investigation of the accuracy with which this correction can be made over the north-eastern and tropical Atlantic Ocean using data at 3.7, 11 and 12 μm wavelengths from the Advanced Very High Resolution Radiometer (AVHRR/2) on the NOAA-7 satellite, and the results are used as a test of atmospheric transmittance models. Simulations of atmospheric transmittances based on line-by-line calculations, using published line listings and experimental data on the water vapour ‘continuum’ absorption, provide regression relationships which permit the s.s.t. to be calculated from the brightness temperatures measured in each channel. New algorithms for both the ‘split window’ (11 and 12 μm) and the ‘triple window’ (3.7, 11 and 12 μm) have been derived for a range of airmasses from 1 to 2 to enable the s.s.t. to be retrieved from a 2280 km wide swath centred on the sub-satellite track. To test the validity of the simulations, the s.s.t. values derived from the satellite measurements were compared with near-coincident in situ measurements from oceanographic research ships. The absence of significant bias (˜0.1 K) in the comparison constitutes an important experimental verification of the atmospheric transmittance model used in the simulations, and the r.m.s. difference between ship and satellite values indicates that daytime measurement of s.s.t. using the ‘split-window’ can be made to an accuracy of about ±0.6 K, in the eastern North Atlantic. Some possible sources of this uncertainty are discussed.

Satellite multichannel infrared measurements of sea surface temperature of the N.E. Atlantic Ocean using AVHRR/2

The measurement of global sea-surface temperature (s.s.t.) from space, with high absolute accuracy, is one of the important requirements of the World Climate Research Programme (W.C.R.P.). This paper considers the definition of measurement aims based on considerations of specific types of scientific problem, and gives as examples discussion of two particular problems, first the possible influence of Pacific s.s.t. on the lower stratosphere, and second the role of s.s.t. in the cloud-climate feedback process. Following this, a brief review is presented on current status in satellite measurements of s.s.t. with both infrared and microwave techniques, and the paper concludes with a description of a future s.s.t.-measuring instrument, the Along-Track Scanning Radiometer (ATSR).

R. W. Saunders

Papers

Satellite multichannel infrared measurements of sea surface temperature of the N.E. Atlantic Ocean using AVHRR/2

Observations of sea-surface temperature for climate research