The NASA Scatterometer Climate Record
Pathfinder (SCP) is a NASA sponsored project to develop scatterometer-based
data time series to support climate studies of the Earth's cryosphere
and biosphere. Originally developed to measure winds over the ocean
from space, scatterometer data has proved to be very useful in a
variety of studies including polar ice and tropical vegetation.
Because the scatterometer radar signal can penetrate the surface,
a scatterometer can observe subsurface/subcanopy climate-related
features.
The launch of Seasat, carrying a Ku-band scatterometer (SASS),
in 1978 provided a baseline against which studies of global change
can be measured. Other missions have followed SASS, including the
C-band European Space Agency (ESA) Earth Remote Sensing (ERS) -1
and -2 missions (1992+), the NASA Scatterometer (NSCAT) mission
in 1996-97, SeaWinds on QuikSCAT (1999+), and SeaWinds on ADEOS-II
(2002). With their rapid global coverage, day or night and all-weather
operation, scatterometers offer a unique tool for long-term climate
studies. The goal of the SCP is to provide scatterometer-based datasets
to researchers involved in climate studies.
The SCP datasets are based on a time series of enhanced resolution
images made from the scatterometer backscatter (sigma0) measurements
using the Scatterometer Image Reconstruction (SIR) and SIR w/filtering
algorithms. For the highest possible spatial resolution (as well
as to ensure full coverage over the images) multiple orbit passes
are combined. For SASS, NSCAT, and ERS, images of sigma0 at 40 deg
incidence angle (A) in dB and the slope of sigma0 versus incidence
angle (B) in dB/deg are made. For SeaWinds on sigma0 images at the
observation incidence angle are made. In addition to these images,
a number of ancillary images and products are generated include
sea ice extent maps and sea ice motion data sets.
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