New paper finds significant decrease in cloudiness over the US past 30 years

A paper published today in the Journal of Climate finds a significant decrease in cloudiness over the contiguous United States during the past 30 years. According to the authors,

A loss of ~4.2% total cloudiness is observed between 1982 and 2012 over a North American domain centered over the contiguous United States.

The paper adds to others finding decreased cloudiness and "global brightening" due to fewer clouds and aerosols beginning in the 1980's [or perhaps earlier since satellite records only exist since 1979]. Most or all global warming over the past 30 years could be attributable to global brightening rather than increased CO2. A mere 1-2% change in cloudiness is sufficient to cause either global warming or cooling. 

Journal of Climate 2014 ; e-View

doi: http://dx.doi.org/10.1175/JCLI-D-14-00068.1

Entering the Era of 30+ Year Satellite Cloud Climatologies: A North American Case Study

Michael J. Foster*

Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin-Madison, Wisconsin, USA. Email: Mike.foster@ssec.wisc.edu

Andrew Heidinger

Center for Satellite Applications and Research, NESDIS, NOAA, Madison, Wisconsin, USA. Email:Andrew.Heidinger@noaa.gov

Abstract

The emergence of satellite-based cloud records of climate-length and quality hold tremendous potential for climate model development, climate monitoring, and studies on global water cycling and its subsequent energetics. This article examines the more than thirty-year PATMOS-x AVHRR cloudiness record over North America and assesses its suitability as a climate-quality data record. A loss of ~4.2% total cloudiness is observed between 1982 and 2012 over a North American domain centered over the contiguous United States. While ENSO can explain some of the observed change, a weather state clustering analysis identifies shifts in weather patterns that result in loss of water cloud over the Great Lakes and cirrus over southern portions of the United States. We characterize the radiative properties of the shifting weather states, and the results suggest that extended cloud satellite records may prove useful tools for increasing our knowledge of cloud feedbacks – a long-standing issue in the climate change community.