Richard W. Katz
Rick Katz (left) and colleague; photo taken near CSIRO branch in Perth, Australia. Research Highlights (FY07):
During FY07, Dr. Richard Katz worked on a number of research projects including:
Verification of forecasts of weather extremes
Having already applied the proposed approach to the verification of forecasts of temperature extremes (in the context of the fruit-frost problem), Katz extended it to the verification of forecasts of precipitation extremes as well. In this case, making use of extreme value theory in forecast verification results in much more of an improvement.
Simulation of extremes by stochastic weather generators
In collaboration with postdoc Eva Furrer (GSP), Katz worked on improving the simulation of extremes by stochastic weather generators. At present, a major limitation of climate scenarios produced by weather generators is the unrealistic treatment of high precipitation amounts. The proposed improvements involve modeling the upper tail of the distribution of daily precipitation amount by either a generalized Pareto or a stretched exponential.
Climatological bounds on extremes
In collaboration with John Henry (graduate student in statistics at Oregon State Univ.), Katz worked on the development of methodology from extreme value theory to estimate the upper bound on a distribution in the possible presence of a trend. In collaboration with Joanie Kleypas, the new method will be applied to extreme high sea surface temperatures in the tropics to ascertain whether increasing trends are consistent with the thermostat hypothesis. Such research has important implications for assessing the potential impacts of global warming on coral reefs.
Statistics of economic damage from extreme events
In collaboration with Matt Coleman (former SOARS protege) and George Young (Coleman's advisor at Penn. St. Univ. ), a stochastic model for the economic damage from hurricanes, originally developed by Katz and based on the concept of a “random sum,” has been revisited. Using updated hurricane damage data for the U.S. recently produced by Roger Pielke, Jr. ( Univ. of Colorado ) and colleagues, the focus is on the detection of trends, particularly in the rate of occurrence and damage of the most intense hurricanes. Such work should contribute to resolving the controversy over whether global warming is having an impact on hurricane damage.
Communication about extremes in a changing climate
In collaboration with SOARS protégé Marcus Walter, the question of how best to extend the concepts of “return period” and “return level,” used to communicate the uncertainty about an extreme event, to a changing climate has been examined. Under a stationary climate, these concepts can be interpreted in terms of either the expected waiting time until the next event or in terms of the expected number of events. Through application to stream flow time series in which human interference has induced non-stationarity (i.e., either building a dam or developing the water basin), it is demonstrated that only one of these two interpretations can be retained under climate change.
Tools for biocomplexity in the environment
The overarching goal of this activity is to develop tools that facilitate end-to-end uncertainty analysis in assessments of the economic impacts of seasonal to annual variations in climate on agriculture. An improved stochastic weather generator for producing scenarios of daily weather has just been developed, based on the statistical approach known as generalized linear modeling (GLM). The improvements include being easy to program, straightforward to incorporate covariates such as the El Ni ñ o-Southern Oscillation phenomenon, and amenable to uncertainty analysis. For more information about this newly developed GLM weather generator, see www.image.ucar.edu/~eva/GLMwgen/index.shtml.
Highlights of Other Activities (FY07):
CSIRO course
Katz taught a short course on Statistics of Extremes in Climate Change in Melbourne, Australia as part of a two-week visit to the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia. The course was attended by over 50 researchers from across Australia.
NZ Lecture tour
Katz gave a series of talks at several universities as well as at the National Institute of Water and Atmospheric Research (NIWA) during a three-week lecture tour sponsored by New Zealand Institute of Mathematics and its Applications and NIWA. His lectures included topics such as climate scenario generation for assessment of economic impacts on agriculture.
Use of Weather Forecasts in Decision Making
Katz participated in two workshops geared toward an integrated approach to the use of weather forecasts: A Forecast Integration Workshop (“Doing Something About the Weather”) at the Naval Postgraduate School in Monterey, CA and a Workshop on Meteorology meets Social Science: Risk, Forecast and Decision at the UK Met Office in Exeter.
Recent Publications:
Apipattanavis, S., G. Podesta, B. Rajagopalan, and R.W. Katz, 2007: A semiparametric multivariate and multisite weather generator. Water Resources Research, doi:10.1029/2006WR005714, in press.
Furrer, E.M., and R.W. Katz, 2007: Generalized linear modeling approach to stochastic weather generators. Climate Research , 34, 129-144.
Harper, B.R., R.W. Katz, and R.C. Harriss, 2007: Statistical methods for quantifying the effect of the El Nino-Southern Oscillation on wind power in the North Great Plains of the United States. Wind Engineering, 31, 123-137.
Katz, R.W., 2007: Environmental sciences. In Statistical Analysis of Extreme Values with Applications to Insurance, Finance, Hydrology and Other Fields (Third Edition), R.-D. Reiss and M. Thomas, Birkhäuser, Basel, Switzerland , pp. 353–367.
Letson, D., C.E. Laciana, F.E. Bert, E.U. Weber, R.W. Katz, X.I. Gonzalez, and G.P. Podestá, 2007: Value of perfect ENSO phase predictions for agriculture: Evaluating the impact of land tenure and decision objectives. Climatic Change (submitted).
Zheng, X., and R.W. Katz , 2007: Simulation of spatial dependence in precipitation using multi-site rainfall generators. Water Resources Research (submitted).
Zheng, X., and R.W. Katz , 2007: Mixture model of generalized chain-dependent processes and its application to simulation of interannual variability of daily rainfall. Journal of Hydrology (submitted).
Presentations (FY07):
Katz, R.W. , and E.M. Furrer, 2007: "Improving the simulation of extreme events by stochastic weather generators." 10th International Meeting on Statistical Climatology, Beijing , China. [pdf file]
Katz, R.W., 2007: "Uncertainty, Optimal Use, and Economic Value of Weather Forecasts." COMET Mesoscale Analysis and Prediction Course, Boulder, CO. [pdf file]
Katz, R.W., 2007: "Forecast verification of extremes: Use of extreme value theory." University of Exeter, UK. [pdf file]
Katz, R.W., 2007: "Quantifying the economic value of weather forecasts: Review of methods and results." Workshop on Meteorology meets Social Science: Risk, Forecast and Decision , UK Met Office, Exeter. [pdf file]
Katz, R.W., 2007: "Background on extreme value theory with emphasis on climate applications." Short Course on Statistics of Extremes in Climate Change, CSIRO, Melbourne, Australia. [pdf file]
Katz, R.W., 2007: "Application of extreme value theory to climate change." Short Course on Statistics of Extremes in Climate Change, CSIRO, Melbourne, Australia. [pdf file]
Katz, R.W., 2007: "Assessing the quality and economic value of weather and climate forecasts." Colorado School of Mines. [pdf file]
Katz, R.W. , and E.M. Furrer, 2007: "Generalized linear modeling approach to stochastic weather generators." American Meteorological Society, 19th Conference on Climate Variability and Change, San Antonio , TX. [pdf file]
Katz, R.W., 2007: "Economic value of forecasts." Forecast Integration Workshop , Naval Postgraduate School, Monterey, CA [pdf file]
Katz, R.W., 2006: "Hidden and not-so-hidden Markov models: Implications for environmental data analysis." Auckland , Otago, and Victoria Universities, New Zealand. [pdf file]
Katz, R.W., 2006: "Forecast verification of extremes: Use of extreme value theory." National Institute of Water & Atmospheric Research, Wellington, New Zealand. [pdf file]
Katz, R.W. , and E.M. Furrer, 2006: "Generalized linear modeling approach to stochastic weather generators." National Institute of Water & Atmospheric Research, Wellington, New Zealand. [pdf file]
Katz, R.W., 2006: "Dynamics of coupled natural and human systems: Climate, agriculture, and complexity in the Argentine Pampas." NCAR/ISSE informal talk, Boulder, CO. [pdf file]
Katz, R.W., 2006: "Stochastic modeling of hurricane damage under climate change." Laboratoire des Sciences du Climate et de l'Environnement, Gif-sur-Yvette, France. [pdf file]
Funding sources:
This research is supported by the National Science Foundation, including special funds from the Biocomplexity in the Environment (BE) / Coupled Natural-Human (CNH) Systems program.