Research Interests

To study the carbon cycle I put together a simple global model of seasonal carbon dioxide exchange between the atmosphere and land biosphere and used it in an atmospheric tracer/circulation model to quantify the contribution of different ecosystems to the seasonal cycle of carbon dioxide at the remote marine-observing sites. In synthesizing the distributions of fossil-fuel carbon dioxide emission with the available atmospheric and oceanic carbon observations, it was found that a principal ocean sink was incompatible with the north-south gradient of carbon dioxide in the atmosphere. Matching both the global carbon budget and the hemispheric carbon dioxide gradient demanded a land sink in middle latitudes in the northern hemisphere. I have also studied the cycles of other trace species: methane from saturated soils, dust from dry soils, and more recently iron in the upper ocean. The fine dust is both radiatively important and a source of iron to support marine productivity in the remote ocean. More recently I have progressed toward a comprehensive climate-biogeochemistry model by coupling interactive land and carbon cycles into the National Center for Atmospheric Research community climate system model. The goal is to investigate the co-evolution of climate and to trace past and future gases.

Membership Type


Election Year


Primary Section

Section 16: Geophysics

Secondary Section

Section 63: Environmental Sciences and Ecology