2011 - Cooperative Institute for Research in Environmental Sciences ...

GMD-05OzoneDepletion
FEDERAL LEADS: JAMES ELKINS, STEPHEN MONTZKA
AND SAM OLTMANS
CIRES LEAD: FRED MOORE
NOAA Goal 2: Climate
Project Goal: Understanding the production and fate of ozone
and the compounds that deplete it is a focal point of collaborative
CIRES research with ESRL’s Global Monitoring and Chemical
Sciences divisions. Stratospheric Ozone Measurements: Measure
ozone declines during the past two decades at northern
hemispheric midlatitudes and the tropics, and characterize
dramatic ozone depletions over Antarctica. Ozone-Depleting
Gases: Conduct research in the troposphere, stratosphere,
oceans, polar snowpack and terrestrial ecosystems in an effort
to characterize, understand and predict the atmospheric
behavior of gases that cause ozone depletion. Stratospheric
Aerosols: Conduct experiments and measurements on aerosols
to determine their impacts on solar insolation. Stratospheric
Water Vapor: Conduct measurements to determine the change
in water vapor and its coupling with aerosols.
Milestone 1. From flask and in situ measurements of
ozone-depleting substances around the globe, update the
Ozone Depleting Gas Index for 2009 and 2010.
Measurements of long-lived substances that cause stratospheric
ozone depletion were continued at remote sites during
July 2010 through June 2011. A statistical technique was
developed to combine measurements from flask and in situ
programs spanning four decades for several gases (Figure 1).
Figure 1: Global mean mixing ratios of CFC-11 and CFC-12 from 1978
to 2011. NOAA Ozone Depleting Gas Index
ODGI
105
100
95
90
85
80
75
70
65
60
Antarctic
Mid-Latitude
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010
Figure 2: NOAA annual “Ozone Depleting Gas Index” for Antarctic and
mid-latitude regions from 1992 to 2010.
116 CIRES Annual Report 2011
These measurement data are used to update the Ozone-Depleting
Gas Index (Figure 2). The index represents tropospheric
trace-gas abundances weighted by different factors relevant
for different regions of the stratosphere. Actual changes in the
stratospheric abundance of ozone-depleting halogen will be
less than the declines shown in this figure, owing to transportrelated
time lags. The index shows a continued overall decline
in the tropospheric abundance of ozone-depleting substances.
Trace-gas measurement data collected in this program were
also used to draw conclusions about the interannual variability
of certain loss processes. Results for methyl chloroform, in
particular, suggest only small changes in global mean atmospheric
hydroxyl radical (OH) concentrations (Montzka et al.,
2011), in contrast to results from some earlier observational
studies. Data for a number of other gases also suggest small
interannual variability in global mean OH concentrations.
Given the central role the atmospheric hydroxyl radical plays
in global atmospheric chemistry, these results suggest that
the atmosphere’s ability to cleanse itself of many pollutants is
fairly robust.
Product: http://www.esrl.noaa.gov/gmd/hats/
combined/CFC11.html
http://www.esrl.noaa.gov/gmd/hats/combined/CFC12.
html
Milestone 2. Report on the vertical profiles of ozonedepleting
substances from the first three campaigns of
the HIAPER Pole-to-Pole Observations of Greenhouse
Gases mission (HIPPO) in 2010. Submit data to the HIPPO
archive and report on the results at a scientific meeting.
HIAPER (High-performance Instrumented Airborne
Platform for Environmental Research) Pole-to-Pole Observations—also
known as HIPPO—involves the study of carbon
dioxide and other greenhouse gases, aerosols and black
carbon (soot) in the troposphere using the National Science
Foundation (NSF)/National Center for Atmospheric Research
(NCAR) Gulfstream V (GV) research aircraft. The flight path
starts in Broomfield, Colo.; travels as far to the North Pole as
possible from Anchorage, Alaska; and proceeds south across
the Pacific to as far south as the South Pole from Christchurch,
New Zealand, and back to Colorado. There will be five complete
circuits during four seasons. As of June 2011, HIPPO/1,
HIPPO/2, HIPPO/3 and HIPPO/4 have been completed.
More than 120 profiles were taken of the whole troposphere