TRMM (Tropical Rainfall Measuring Mission) Data Set Potential in Climate Controversy By Joanne Simpson, private citizen

I am pleased to be able to post a weblog by Dr. Joanne Simpson who is among the most preeminent scientists of the last 100 years.  Her comments were first distributed on a limited mail group, and are reproduced here with her permission.

 Dr. Joanne Simpson

“Since I am no longer affiliated with any organization nor receive any funding, I can speak quite frankly. For more than a decade now “global warming” and its impacts has become the primary interface between our science and society. A large group of earth scientists, voiced in an IPCC[1] statement, have reached what they claim is a consensus of nearly all atmospheric scientists that man-released greenhouse gases are causing increasing harm to our planet. They predict that most icepacks including those in the Polar Regions, also sea ice, will continue melting with disastrous ecological consequences including coastal flooding. There is no doubt that atmospheric greenhouse gases are rising rapidly and little doubt that some warming and bad ecological events are occurring. However, the main basis of the claim that man’s release of greenhouse gases is the cause of the warming is based almost entirely upon climate models. We all know the frailty of models concerning the air-surface system. We only need to watch the weather forecasts. However, a vocal minority of scientists so mistrusts the models and the complex fragmentary data, that some claim that global warming is a hoax. They have made public statements accusing other scientists of deliberate fraud in aid of their research funding. Both sides are now hurling personal epithets at each other, a very bad development in Earth sciences. The claim that hurricanes are being modified by the impacts of rising greenhouse gases is the most inflammatory frontline of this battle and the aspect that journalists enjoy the most. The situation is so bad that the front page of the Wall Street Journal printed an article in which one distinguished scientist said another distinguished scientist has a fossilized brain. He, in turn, refers to his critics as “the Gang of Five”.

Few of these people seem to have any skeptical self-criticism left, although virtually all of the claims are derived from either flawed data sets or imperfect models or both. The term “global warming” itself is very vague. Where and what scales of response are measurable? One distinguished scientist has shown that many aspects of climate change are regional, some of the most harmful caused by changes in human land use. No one seems to have properly factored in population growth and land use, particularly in tropical and coastal areas.

What should we as a nation do? Decisions have to be made on incomplete information. In this case, we must act on the recommendations of Gore and the IPCC because if we do not reduce emissions of greenhouse gases and the climate models are right, the planet as we know it will in this century become unsustainable. But as a scientist I remain skeptical. I decided to keep quiet in this controversy until I had a positive contribution to make. That point is to be celebrated in the TRMM 10 year anniversary in a Conference in February, 2008. With a 10-year record the TRMM, users of the data can begin to look for and test for trends. With the TRMM sampling limitations, other data sets, from geosynchronous and other sources are being used now in the group led by Bob Adler. Their products can detect trends in global tropical rain on several scales, including regional.

These patterns can be compared over the past ten years with the patterns predicted ten years ago by the climate models. An example is the Walker circulation, normally with descent of air over the eastern Pacific Ocean and ascent of air over the western Pacific. When this cell weakens, perhaps breaking over the middle Pacific, we have an El Niño. The modelers say that higher greenhouse warming produces recognizable changes in the Walker circulation. What better data is there to test such model results than the tropical rain products from TRMM? While the TRMM data set provides no panacea on the volatile hurricane front, useful information for the several ocean basins relating the rainfall to claimed and observed storm structure can be made if dedicated work is committed. I would be most interested to find out how the distribution of hot towers relates to storm intensity and rain production. Examining the data already posted on the TRMM Website shows that such projects are tractable. The major lack for TRMM data use in testing climate theories is latitude limitation. Global warming impacts appear much more severe in polar latitudes than in tropical regions. The best news is that the Global Precipitation Mission (GPM) is on schedule for a 2013 launch. In conclusion I can just pray that GPM scientists and engineers are as smart and as lucky as we TRMM participants have been.”

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