Robert G. Quayle

Indices of Climate Change for the United States

Abstract A framework is presented to quantify observed changes in climate within the contiguous United States through the development and analysis of two indices of climate change, a Climate Extremes Index (CEI) and a U.S. Greenhouse Climate Response Index (GCRI). The CEI is based on an aggregate set of conventional climate extreme indicators, and the GCRI is composed of indicators that measure changes in the climate of the United States that have been projected to occur as a result of increased emissions of greenhouse gases. The CEI supports the notion that the climate of the United States has become more extreme in recent decades, yet the magnitude and persistence of the changes are not large enough at this point to conclude that the increase in extremes reflects a nonstationary climate. Nonetheless, if impacts due to extreme events rise exponentially with the index, then the increase may be quite significant in a practical sense. Similarly, the positive trend of the U.S. GCRI during the twentieth centu...

Global warming : evidence for asymmetric diurnal temperature change

Analyses of the year-month mean maximum and minimum surface thermometric record have now been updated and expanded to cover three large countries in the Northern Hemisphere (the contiguous United States, the Soviet Union, and the Peoples Republic of China). They indicate that most of the warming which has occurred in these regions over the past four decades can be attributed to an increase of mean minimum (mostly nighttime) temperatures. Mean maximum (mostly daytime) temperatures display little or no warming. In the USA and the USSR (no access to data in China) similar characteristics are also reflected in the changes of extreme seasonal temperatures, e.g., increase of extreme minimum temperatures and little or no change in extreme maximum temperatures. The continuation of increasing minimum temperatures and little overall change of the maximum leads to a decrease of the mean (and extreme) temperature range, an important measure of climate variability. The cause(s) of the asymmetric diurnal changes are uncertain, but there is some evidence to suggest that changes in cloud cover plays a direct role (where increases in cloudiness result in reduced maximum and higher minimum temperatures). Regardless of the exact cause(s), these results imply that either: (1) climate model projections considering the expected change in the diurnal temperature range with increased levels of the greenhouse gases are underestimating (overestimating) the rise of the daily minimum (maximum) relative to the maximum (minimum), or (2) the observed warming in a considerable portion of the Northern Hemisphere landmass is significantly affected by factors unrelated to an enhanced anthropogenically-induced greenhouse effect.

A Historical Perspective of U.S. Climate Divisions

The history of climatic divisions in the contiguous United States has been pieced together from fragmentary documentation. Each of the 48 contiguous states has been subdivided into climatic divisions. Divisional boundaries are now standardized, and a set of climatic variables for time-invariant divisional boundaries has been compiled for the period of record beginning in 1895. This paper documents the origins of climatic divisions, the computational methodology of an area-invariant divisional dataset maintained by the National Climatic Data Center, and the strengths and weaknesses of divisional data.

Effects of Recent Thermometer Changes in the Cooperative Station Network

During the past five years, the National Weather Service (NWS) has replaced over half of its liquid-in-glass maximum and minimum thermometers in wooden Cotton Region Shelters (CRSs) with thermistor-based Maximum–Minimum Temperature Systems (MMTSs) housed in smaller plastic shelters. Analyses of data from 424 (of the 3300) MMTS stations and 675 CRS stations show that a mean daily minimum temperature change of roughly +0.3°C, a mean daily maximum temperature change of−0.4°C, and a change in average temperature of −0.1 °C were introduced as a result of the new instrumentation. The change of −0.7°C in daily temperature range is particularly significant for climate change studies that use this element as an independent variable. Although troublesome for climatologists, there is reason to believe that this change (relative to older records) represents an improvement in absolute accuracy. The bias appears to be rather sharp and well defined. Since the National Climatic Data Center (NCDC) station history database...

Heating Degree Day Data Applied to Residential Heating Energy Consumption

Abstract Site-specific total electric energy and heating oil consumption for individual residences show a very high correlation with National Weather Service airport temperature data when transformed to heating degree days. Correlations of regional total residential electrical consumption with airport heating degree days for about 40 000 dwelling units in an area of ∼6500 km2 over an 11-year period indicate that temperature is a dominant cause of short-term usage fluctuations. Cost increases since 1973 appear to have only temporarily slowed the growth rate in consumption. A time series of national population-weighted heating degree day totals for the period 1898–1978 provides a scenario of possible variations of weather-related residential energy consumption.

The Climate of the United States since 1895: Spatial and Temporal Changes

Abstract Time series of temperature and precipitation weighted by area and grouped by season for each of the 48 contiguous United States were analyzed. Within an 83-year period of record (1895–1977) three subperiods or climatic regimes are identified and the differences in their means and standard deviations plotted and analyzed. The statistical significance of the changes in the mean was calculated by using a two-tailed t test; for changes in the standard deviation, the F-ratio test was used. The variation patterns suggest that an east-west mode for changes in both temperature and precipitation is dominant over the continental United States. Over the past 25 years the average temperature of the United States has decreased∼1°F (0.6°C) from the relatively warm interval of the 1920s to the middle 1950s. However, most of this cooling has occurred in the eastern United States. In winter, for example, the southeastern United States cooled ∼3°F (1.7°C), whereas the Far West actually recorded warmer mean tempe...

Detecting climate variations and change : new challenges for observing and data management systems

Abstract Several essential aspects of weather observing and the management of weather data are discussed as related to improving knowledge of climate variations and change in the surface boundary layer and the resultant consequences for socioeconomic and biogeophysical systems. The issues include long-term homogeneous time series of routine weather observations; time- and space-scale resolution of datasets derived from the observations; information about observing systems, data collection systems, and data reduction algorithms; and the enhancement of weather observing systems to serve as climate observing systems. Although much has been learned from existing weather networks and methods of data management, the system is far from perfect. There are several vital areas that have not received adequate attention. Particular improvements are needed in the interaction between network designers and climatologists; operational analyses that focus on detecting and documenting outliers and time-dependent biases wit...

The Greenhouse Effect in Central North America: If Not Now, When?

Climate models with enhanced greenhouse gas concentrations have projected temperature increases of 2� to 4�C, winter precipitation increases of up to 15 percent, and summer precipitation decreases of 5 to 10 percent in the central United States by the year 2030. An analysis of the climate record over the past 95 years for this region was undertaken in order to evaluate these projections. Results indicate that temperature has increased and precipitation decreased both during winter and summer, and that the ratio of winter-to-summer precipitation has decreased. The signs of some trends are consistent with the projections whereas others are not, but none of the changes is statistically significant except for maximum and minimum temperatures, which were not among the parameters predicted by the models. Statistical models indicate that the greenhouse winter and summer precipitation signal could have been masked by natural climate variability, whereas the increase in the ratio of winter-to-summer precipitation and the higher rates of temperature change probably should have already been detected. If the models are correct it will likely take at least another 40 years before statistically significant precipitation changes are detected and another decade or two to detect the projected changes of temperature.

The 1980 Summer Heat Wave and Drought in Historical Perspective

Abstract Economic losses during the hot, dry summer of 1980 were estimated at

An operational near‐real‐time global temperature index

16 billion. Despite these substantial economic losses, analyses of historical (1895–1980) monthly temperature and precipitation data across the 48 contiguous United States indicate that conditions could easily have been worse. Much more hostile conditions have existed in the past, particularly during the 1930s and the 1950s. However, the summer of 1980 does stand out from the past two decades as an extreme anomaly across the southern and southeastern United States. Analyses of Palmers (1965) drought severity index, Paimers soil moisture abnormality index, and values of precipitation minus potential evapotranspiration are used in the assessment of drought. Monthly mean temperature and population weighted cooling degree days as related to electrical energy consumption are used to assess the summer heat wave of 1980.