Martha P. Butler

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Mixing ratios of CO 2 often change abruptly in the presence of inclement weather and low pressure systems. Water vapor mixing ratio, temperature, wind speed, and wind direction data are used to infer that the abrupt changes in CO 2 mixing ratios at a site in northern Wisconsin are due to tropospheric mixing, horizontal transport, or a combination of both(More)
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Executive Summary Since Autumn 1998, the MONARC project [1] has provided key information on the design and operation of the worldwide-distributed Computing Models for the LHC experiments. This document summarises the status of MONARC and the results of the project's first two Phases. A third Phase, summarised at the end of this report, is now underway. The(More)
[1] Convective turbulence within the atmospheric boundary layer (ABL) and movement of the ABL over the surface results in a large spatial (10 4 –10 5 km 2) integration of surface fluxes that affects the CO 2 and water vapor mixing ratios. We apply quasi-equilibrium concepts for the terrestrial ABL to measurements of CO 2 and water vapor made within the ABL(More)
The aim of this case study is to examine the surface layer CO 2 budget and possible impacts of advection on the 20 km scale on estimates of net ecosystem–atmosphere exchange (NEE) of CO 2 under windy conditions. The advection terms in the CO 2 mixing ratio conservation equation are computed using data from two flux towers 20 km apart in a forested area in(More)
[1] Difficulties in estimating terrestrial ecosystem CO 2 fluxes on regional scales have significantly limited our understanding of the global carbon cycle. This paper presents an effort to estimate daytime CO 2 fluxes over a forested region on the scale of 50 km in northern Wisconsin, USA, using the tall-tower-based mixed layer (ML) budget method. Budget(More)
The dimensionless bottom-up and top-down gradient functions in the convective boundary layer (CBL) are evaluated utilizing long-term well-calibrated carbon dioxide mixing ratio and flux measurements from multiple levels of a 447-m tall tower over a forested area in northern Wisconsin, USA. The estimated bottom-up and top-down functions are qualitatively(More)
Integrated assessment models for climate change (IAMs) couple representations of economic and natural systems to identify and evaluate strategies for managing the effects of global climate change. In this study we subject the Dynamic Integrated model of Climate and Economy (DICE), an IAM of lower-bound complexity , to a comprehensive global sensitivity(More)
  • M. Butler
  • 2004
The last decade has seen a vast growth in technologies suitable for implementation into learning frameworks. Web and communications technologies are now being used in the delivery of course materials to both on-campus and distance education students. Primary application of these technologies however has been in simple replication of existing processes. This(More)
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