Chapter 14
The Validation of Sea Surface Temperature
Retrievals from Spaceborne Infrared
Radiometers
Peter J. Minnett
14.1 Introduction
There are uncertainties associated with all measurements, and the magnitude of the
uncertainties imposes restrictions on how the measurements should be applied or
interpreted. The uncertainties can result from a variety of causes that relate to the
nature of the variable being measured, and how the measurements are being made.
Furthermore the techniques employed to assess the magnitude and characteristics of
the uncertainties are also prone to error.
In the case of Sea Surface Temperature (SST) derived from measurements taken
by infrared radiometers on earth-observing satellites, the sources of uncertainties
can be divided into those that result from the characteristics of the radiometer, and
how well the measurements are calibrated, and those that arise from imperfections
in the atmospheric correction algorithm that is applied to remove the effects of the
intervening atmosphere, including identifying the effects of clouds and aerosols.
Typically, for want of a better defensible approach, the uncertainties that arise from
the method of validating the satellite-derived SSTs are attributed to the satellite data.
In this chapter we mention the sources of uncertainties in the SST retrieval from
the on-orbit measurements, and focus on how the uncertainties can be determined.
We do not consider directly the physics of the measurement, nor the particulars of
the atmospheric correction algorithms or approaches to cloud screening; these have
recently been reviewed elsewhere (Minnett and Barton, 2010), and some aspects are
discussed elsewhere in this volume. But first we have to establish what is meant by
“SST” and what are desired, or at least acceptable, levels of uncertainties.
14.2 What Is Sea-Surface Temperature?
The radiance measured in space by infrared radiometers has its origin in the skin
layer of the ocean and not in the body of the water below, the “bulk temperature” of
P.J. Minnett (B)
Meteorology and Physical Oceanography, Rosenstiel School of Marine and Atmospheric Science,
University of Miami, Miami, FL 33149-1098, USA
e-mail: pminnett@rsmas.miami.edu
229
V. Barale et al. (eds.), Oceanography from Space,
DOI 10.1007/978-90-481-8681-5_14, C
Springer Science+Business Media B.V. 2010
The Validation of Sea Surface Temperature
Retrievals from Spaceborne Infrared
Radiometers
Peter J. Minnett
14.1 Introduction
There are uncertainties associated with all measurements, and the magnitude of the
uncertainties imposes restrictions on how the measurements should be applied or
interpreted. The uncertainties can result from a variety of causes that relate to the
nature of the variable being measured, and how the measurements are being made.
Furthermore the techniques employed to assess the magnitude and characteristics of
the uncertainties are also prone to error.
In the case of Sea Surface Temperature (SST) derived from measurements taken
by infrared radiometers on earth-observing satellites, the sources of uncertainties
can be divided into those that result from the characteristics of the radiometer, and
how well the measurements are calibrated, and those that arise from imperfections
in the atmospheric correction algorithm that is applied to remove the effects of the
intervening atmosphere, including identifying the effects of clouds and aerosols.
Typically, for want of a better defensible approach, the uncertainties that arise from
the method of validating the satellite-derived SSTs are attributed to the satellite data.
In this chapter we mention the sources of uncertainties in the SST retrieval from
the on-orbit measurements, and focus on how the uncertainties can be determined.
We do not consider directly the physics of the measurement, nor the particulars of
the atmospheric correction algorithms or approaches to cloud screening; these have
recently been reviewed elsewhere (Minnett and Barton, 2010), and some aspects are
discussed elsewhere in this volume. But first we have to establish what is meant by
“SST” and what are desired, or at least acceptable, levels of uncertainties.
14.2 What Is Sea-Surface Temperature?
The radiance measured in space by infrared radiometers has its origin in the skin
layer of the ocean and not in the body of the water below, the “bulk temperature” of
P.J. Minnett (B)
Meteorology and Physical Oceanography, Rosenstiel School of Marine and Atmospheric Science,
University of Miami, Miami, FL 33149-1098, USA
e-mail: pminnett@rsmas.miami.edu
229
V. Barale et al. (eds.), Oceanography from Space,
DOI 10.1007/978-90-481-8681-5_14, C
Springer Science+Business Media B.V. 2010