[Vision2020] NOAA: Review of Four Decades of Scientific Literature Concludes Lower Atmosphere is Warming

[Ted Moffett]

 Tropospheric temperature trends: history of an ongoing controversy

http://onlinelibrary.wiley.com/doi/10.1002/wcc.80/abstract
Abstract

Changes in atmospheric temperature have a particular importance in climate
research because climate models consistently predict a distinctive vertical
profile of trends. With increasing greenhouse gas concentrations, the
surface and troposphere are consistently projected to warm, with an
enhancement of that warming in the tropical upper troposphere. Hence,
attempts to detect this distinct ‘fingerprint’ have been a focus for
observational studies. The topic acquired heightened importance following
the 1990 publication of an analysis of satellite data which challenged the
reality of the projected tropospheric warming. This review documents the
evolution over the last four decades of understanding of tropospheric
temperature trends and their likely causes. Particular focus is given to the
difficulty of producing homogenized datasets, with which to derive trends,
from both radiosonde and satellite observing systems, because of the many
systematic changes over time. The value of multiple independent analyses is
demonstrated. Paralleling developments in observational datasets, increased
computer power and improved understanding of climate forcing mechanisms have
led to refined estimates of temperature trends from a wide range of climate
models and a better understanding of internal variability. It is concluded
that there is no reasonable evidence of a fundamental disagreement between
tropospheric temperature trends from models and observations when
uncertainties in both are treated comprehensively. *WIREs Clim Change* 2010
DOI: 10.1002/wcc.80
----------------------------------------

Discussion of the scientific paper referenced above:
Review of Four Decades of Scientific Literature Concludes Lower Atmosphere
is Warming

November 15, 2010

http://www.noaanews.noaa.gov/stories2010/20101115_warming.html
The troposphere, the lower part of the atmosphere closest to the Earth, is
warming and this warming is broadly consistent with both theoretical
expectations and climate models, according to a new scientific study that
reviews the history of understanding of temperature changes and their causes
in this key atmospheric layer.

Scientists at NOAA, the NOAA-funded Cooperative Institute for Climate and
Satellites (CICS), the United Kingdom Met Office, and the University of
Reading in the United Kingdom contributed to the paper, “Tropospheric
Temperature Trends: History of an Ongoing Controversy,” a review of four
decades of data and scientific papers to be published today by Wiley
Interdisciplinary Reviews - Climate
Change<http://onlinelibrary.wiley.com/doi/10.1002/wcc.80/abstract>,
a peer-reviewed journal.

The paper documents how, since the development of the very first climate
models in the early 1960s, the troposphere has been projected to warm along
with the Earth’s surface because of the increasing amounts of greenhouse
gases in the atmosphere. This expectation has not significantly changed even
with major advances in climate models and is in accord with our basic
physical understanding of atmospheric processes.

In the 1990s, observations did not show the troposphere, particularly in the
tropics, to be warming, even though surface temperatures were rapidly
warming. This lack of tropospheric warming was used by some to question both
the reality of the surface warming trend and the reliability of climate
models as tools. This new paper extensively reviews the relevant scientific
analyses — 195 cited papers, model results and atmospheric data sets — and
finds that there is no longer evidence for a fundamental discrepancy and
that the troposphere is warming.

“Looking at observed changes in tropospheric temperature and climate model
expectations over time, the current evidence indicates that no fundamental
discrepancy exists, after accounting for uncertainties in both the models
and observations,” said Peter Thorne, a senior scientist with CICS in
Asheville, N.C., and a senior researcher at North Carolina State University.
CICS is a consortium jointly led by the University of Maryland and North
Carolina State University.

This paper demonstrates the value of having various types of measurements —
from surface stations to weather balloons to satellites — as well as
multiple independent analyses of data from these observation systems.

“There is an old saying that a person with one watch always knows what time
it is, but with two watches one is never sure,” said Thomas Peterson, lead
scientist at NOAA’s National Climatic Data Center. “The controversy started
with the production of the first upper-air temperature ‘watch’ in 1990, and
it was only later when multiple additional ‘watches’ were made by different
‘manufacturers’ that we learned that they were each a few minutes off.
Although researchers all agree the temperature is increasing, they disagree
how much.”

And while this is the first comprehensive review of the scientific
literature on this topic, it is not the last word on the tropospheric
temperature trend.

“Looking to the future, it is only through robust and varied observations
and data analyses that we can hope to adequately understand the tropospheric
temperature trend,” said Dian Seidel, a NOAA scientist at the Air Resources
Laboratory, in Silver Spring, Md.
The study was funded by UK Department of Energy and Climate Change, the UK
Department of Environment, Food and Rural Affairs and NOAA.
-------------------------------------------
Vision2020 Post: Ted Moffett
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.fsr.com/pipermail/vision2020/attachments/20101116/2b371dd7/attachment-0001.html