Linear Trends and Closures of 10-yr Observations of AIRS Stratospheric Channels

Details

• Journal Title:
  Journal of Climate
• Personal Author:
  Pan, Fang ; Huang, Xianglei ; Strow, L. Larabbe ; Guo, Huan
• NOAA Program & Office:
  GFDL (Geophysical Fluid Dynamics Laboratory) ; OAR (Oceanic and Atmospheric Research)
• Description:
  The Atmospheric Infrared Sounder (AIRS) level-1b radiances have been shown to be well calibrated (~0.3 K or higher) and have little secular drift (~4 mK yr−1) since operation started in September 2002. This paper investigates the linear trends of 10 years (2003–12) of AIRS global-mean radiances in the CO2 v2 band that are sensitive to emissions from the stratosphere (stratospheric channels). AIRS lower-stratospheric channels have a cooling trend of no more than 0.23 K decade−1 whereas the midstratospheric channels consistently show a statistically significant cooling trend as large as 0.58 K decade−1. The 95% confidence interval for the trend is ~±0.20 K decade−1. Two sets of synthetic AIRS radiances are computed using the principal component–based radiative transfer model (PCRTM), one based on a free-running GFDL Atmospheric Model, version 3 (AM3), over the same period and one based on ERA-Interim. The GFDL AM3 simulations overestimate the cooling trends in the mid- to upper-stratospheric channels but slightly underestimate them in the lower-stratospheric channels. The synthetic radiances based on ERA-Interim, however, have statistically significant positive trends at virtually all stratospheric channels. This confirms the challenge to the GCM modeling and reanalysis community to create a better simulation or assimilation of the stratospheric climate. It is shown that the linear trends in AIRS radiances can be reproduced to a large extent by the spectral radiative kernel technique and the trends from the AIRS L2 temperature retrievals and from the change of CO2. This suggests a closure between AIRS L1 radiances and L2 retrievals and the potential merit of AIRS data in studies of stratosphere changes.
• Keywords:
  Atmospheric Science
• Source:
  Journal of Climate, 28(22), 8939-8950
• DOI:
  https://doi.org/10.1175/jcli-d-15-0418.1
• ISSN:
  0894-8755 ; 1520-0442
• Format:
  PDF
• Publisher:
  American Meteorological Society
• Document Type:
  Journal Article
• Rights Information:
  Other
• Compliance:
  Library
• Main Document Checksum:
  urn:sha-512:896a008e76da325b45ea59e3cdd45cf9bb94f1f31f4271912951a94dd5a44a6f93b4d8354a5ae0730008ea85e56f71d92cbf09eb9410ebfd4bec1cc189f64eb4
• Download URL:
  https://repository.library.noaa.gov/view/noaa/64121/noaa_64121_DS1.pdf
• File Type:
  [PDF - 1.36 MB ]