https://phys.org/news/2019-04-nasa-global-trends.html
April 16, 2019
NASA study verifies global warming trends
by Institute of Physics
A new study by researchers from NASA has verified the accuracy of recent
global warming figures.
The team used measurements of the 'skin' temperature of the Earth taken
by a satellite-based infrared measurement system called AIRS
(Atmospheric Infra-Red Sounder) from 2003 to 2017.
They compared these with station-based analyses of surface air
temperature anomalies—principally the Goddard Institute for Space
Studies Surface Temperature Analysis (GISTEMP).
They found a high level of consistency between the two datasets over the
past 15 years. Their results are published today in Environmental
Research Letters.
Commenting on the study, lead author Dr. Joel Susskind, from NASA's
Goddard Space Flight Center, said: "AIRS data complement GISTEMP because
they are at a higher spatial resolution than GISTEMP, and have more
complete global coverage.
"Both data sets demonstrate the earth's surface has been warming
globally over this period, and that 2016, 2017, and 2015 have been the
warmest years in the instrumental record, in that order.
"This is important because of the intense interest in the detail of how
estimates of global and regional temperature change are constructed from
surface temperature data, and how known imperfections in the raw data
(due to station moves, gaps, instrument and practice changes, urban heat
island effects) are handled."
AIRS data reflects skin temperature at the surface of the ocean, land,
and snow/ice covered regions. Surface-based data are a blend of two
metre surface air data anomalies over land, and bulk sea surface
temperature anomalies in the ocean.
To compare the two, the researchers constructed monthly grid point
climatologies for each calendar month and for each set of data, by
averaging the monthly values over 2003 to 2017, with anomalies for a
given month, in a given year, defined as the difference of the grid
point value for that month from its monthly climatology.
Co-author Dr. Gavin Schmidt, from NASA's Goddard Institute for Space
Studies, said: "Interestingly, our findings revealed that the
surface-based data sets may be underestimating the temperature changes
in the Arctic. This means the warming taking place at the poles may be
happening more quickly than previously thought.
"Our work also shows that complementary satellite-based surface
temperature analyses serve as an important validation of surface-based
estimates. They may point the way to make improvements in surface-based
products that can perhaps be extended back many decades."
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