RESEARCH OVERVIEW - Alan K. Betts

A brief overview of my research.

This decade, I have revisited the BL cloud and climate change problem over land with the equilibrium BL model and a coupled carbon cycle, and completed a review of LBA research insights into land-atmosphere coupling. I have contributed to two global studies, one comparing land surface heat flux estimates and a second looking at recent trends in the tropical hydrological cycle. I contributed to a paper that evaluates the cloud fields in three reanalyses using ARM data from the Southern Great Plains site. I also contributed to two papers, formulating a new probabalistic-bulk model for the coupled mixed later and shallow convection layers.

In recent years, I have started to shift my focus to address the impact of global change locally in Vermont. I am working on Vermont climate change indicators; and using the Seasonal climate transitions to explain climate feedback processes to an interested public. I have also worked with the State Agency of Natural Resources on climate change adaptation planning. The past seven years (2005-2012) my work was supported by the National Science Foundation under Grant AGS-0529797 - you can see a highlight here.

My aim is to write papers that can be understood by both traditional scientific audiences, other professionals and the public. For this we need receptive journals – because not all our traditional journals accept that ‘plain English’ has real advantages over technical jargon! So in parallel, I am writing articles to broaden our collective understanding of our responsibility as Earth scientists for clear, open public communication. I also write articles for the Sunday environment section of two Vermont newspapers, based on a different model, summarized in Environmental journalism revisited. I also lecture extensively around the Vermont. Humanity will be unable to deal with climate change, both in terms of mitigation and adaptation, until a broad spectrum of society is fluent in discussing the issues and the choices we face. It is time for scientists to consider more deeply our responsibilities to society and to the Earth.

My research in the 2000s addressed land-surface-atmosphere-cloud coupling, the field programs LBA and BOREAS, and reanalysis evaluation. This was partly data analysis, partly evaluation of models with data, and partly developing new conceptual frameworks. I worked on an idealized framework for studying the diurnal cycle over land over Amazonia. I worked extensively on quantifying the surface SW impact of clouds, using the concept of effective cloud albedo. This gives symmetric roles to the surface and clouds in the surface energy budget. I developed several important idealized models which coupled land-surface processes to radiative processes: models for the equilibrium BL over land (with and without vegetation coupling) and for the nocturnal BL and the diurnal cycle. I wrote several important reviews: on understanding global hydrometeorology, land-atmosphere coupling, and the Amazonian boundary layer.

My research in the 1990’s was primarily on land-surface processes: stemming from my participation in FIFE [grassland in Kansas] and BOREAS [boreal forest in Saskatchewan and Manitoba]. A second thread was the evaluation of model errors in operational forecast models and reanalyses at ECMWF and NCEP using these field experiment data and GEWEX data. Major discoveries were the importance of soil water on BL diurnal evolution; soil water-evaporation-precipitation feedback in models, and the hemispheric impact in spring on short-range forecasts of snow albedo errors over the boreal forest (the snow-albedo feedback impact on the forecast problem). This work led to the correction of many forecast model errors. There were a few papers relating to earlier work on tropical climate equilibrium, and two reviews which extended the Betts-Miller scheme. I have archived a copy of the historically important US Senate hearing on “The Role of Clouds in Climate Change", October 7, 1991, which includes my testimony and discussion with Richard Lindzen (otherwise unavailable on the web).

My research in the 1980’s started with a review of convection over the tropical ocean in GATE. I then developed the thermodynamics of air parcel saturation point for conceptually organizing convective and BL processes (an extension of my work in the 1970s). This was applied to several datasets and convective regimes. It led to two important models: the Betts-Miller convective parameterization scheme (which is still in use today) and, when coupled to a radiation code, the Betts-Ridgway model for tropical BL equilibrium for the present climate, a doubled CO2 climate and the ice-age climate.

My research in the 1970’s stemmed:

1) From my PhD work on “Cumulus Convection”, which introduced or extended many important concepts: a mixed layer model for dry convection and the sub-cloud layer; the liquid water potential temperature; and mass, enthalpy and water transport models for shallow convective BLs. This was largely conceptual, but it would be fair to say that it was inspired by my spending a summer in Venezuela in 1969 with Herbert Riehl and the VIMHEX-1969 experiment. I saw each day that afternoon convection was not predictable - until it appeared on the radar!

2) From my field experiment work in the tropics in Venezuela with VIMHEX-1969 and 1972 (the sub-cloud layer, mesoscale systems and traveling squall-lines); and in GATE in the tropical Atlantic – where I was the ‘Convection Subprogram Scientist’ and an ‘Airborne Mission Scientist’ for this very large international program.

So my 70’s research deals with convection and BLs over both the tropical land and the tropical ocean.

My only paper on the 1960's (and my only paper on atmospheric dynamics!) - Betts and McIlveen (1969) - came from noticing that the energy equation is not invariant in a moving reference frame on a rotating planet.

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