Randall S. Cerveny

Weekly cycles of air pollutants, precipitation and tropical cyclones in the coastal NW Atlantic region

Direct human influences on climate have been detected at local scales, such as urban temperature increases and precipitation enhancement, and at global scales,. A possible indication of an anthropogenic effect on regional climate is by identification of equivalent weekly cycles in climate and pollution variables. Weekly cycles have been observed in both global surface temperature and local pollution data sets. Here we describe statistical analyses that reveal weekly cycles in three independent regional-scale coastal Atlantic data sets: lower-troposphere pollution, precipitation and tropical cyclones. Three atmospheric monitoring stations record minimum concentrations of ozone and carbon monoxide early in the week, while highest concentrations are observed later in the week. This air-pollution cycle corresponds to observed weekly variability in regional rainfall and tropical cyclones. Specifically, satellite-based precipitation estimates indicate that near-coastal ocean areas receive significantly more precipitation at weekends than on weekdays. Near-coastal tropical cyclones have, on average, significantly weaker surface winds, higher surface pressure and higher frequency at weekends. Although our statistical findings limit the identification of cause–effect relationships, we advance the hypothesis that the thermal influence of pollution-derived aerosols on storms may drive these weekly climate cycles.

Long-Term Associations between Wind Speeds and the Urban Heat Island of Phoenix, Arizona

Abstract The association between a developing urban heat island and local monthly averaged wind speeds is examined in this investigation. Results from a series of statistical analyses show a significant increase in wind speeds in Phoenix, Arizona during the period of rapid heat island development. The increase in winds is found to be much stronger at 0500 MST than at 1400 MST. Increased instability and the development of a strong heat low circulation in the urban environment are suggested as probable causes for the increased wind speeds.

Climatological Relationships between Tropical Cyclones and Rainfall

Abstract Flooding from tropical cyclone (TC) precipitation has lead in recent years to massive death and loss of property. The identification of climatological linkages between rainfall and TC parameters through study of long-term records would be useful in (i) identifying seasonal predictive climatic parameters to TC development, (ii) producing better precipitation estimates for affected areas, and (iii) developing better parameterizations between storm intensity, latent heat release, and rainfall in hurricane models. This study uses a daily satellite-derived oceanic precipitation record from 1979 to 1995 to determine the rainfall associated with the Atlantic and North Pacific basins over that time period (877 TCs). These data, categorized into 2.5° × 2.5° ocean grid cells, were used to create two precipitation databases. The first uses the surrounding nine grid cells marked from the average position of the tropical cyclone on the day of observation, while the second uses only the center grid cell for th...

Compilation and Discussion of Trends in Severe Storms in the United States: Popular Perception v. Climate Reality

The ongoing greenhouse gas buildup and increase in near-surface air temperatures may have an impact on severe weather events in the United States. Output from some numerical modeling simulations suggests that the atmosphere over mid-latitude land areas could become more unstable in the future thereby supporting an increase in convective activity. However, despite the numerical simulation results, empiricists have been unable generally to identify significant increases in overall severe storm activity as measured in the magnitude and/or frequency of thunderstorms, hail events, tornadoes, hurricanes, and winter storm activity across the United States. There is evidence that heavy precipitation events have increased during the period of historical records, but for many other severe weather categories, the trends have been downward over the past half century. Damage from severe weather has increased over this period, but this upward trend disappears when inflation, population growth, population redistribution, and wealth are taken into account.

Influence of Lunar Phase on Daily Global Temperatures

A newly available data set of daily satellite-derived, lower-tropospheric global temperature anomalies provides an opportunity to assess the influence of lunar phase on planetary temperature. These results reveal a statistically significant 0.02 K modulation between new moon and full moon, with the warmest daily global temperatures over a synodic month coincident with the occurrence of the full moon. Spectral analysis of the daily temperature record confirms the presence of a periodicity that matches the lunar synodic (29.53-day) cycle. The precision of the satellite-based daily temperature record allows verification that the moon exerts a discernible influence on the short-term, global temperature record.

HEAT MORTALITY VERSUS COLD MORTALITY A Study of Conflicting Databases in the United States

Abstract Studies, public reports, news reports, and Web sites cite a wide range of values associated with deaths resulting from excessive heat and excessive cold. For example, in the United States, the National Climatic Data Centers Storm Data statistics of temperature- related deaths are skewed heavily toward heat-related deaths, while the National Center for Health Statistics Compressed Mortality Database indicates the reverse—4 times more people die of “excessive cold” conditions in a given year than of “excessive heat.” In this study, we address the fundamental differences in the various temperature-related mortality databases, assess their benefits and limitations, and offer suggestions as to their use. These datasets suffer from potential incompleteness of source information, long compilation times, limited quality control, and the subjective determination of a direct versus indirect cause of death. In general, these separate mortality datasets should not be combined or compared, particularly with ...

Extreme weather records: Compilation, adjudication, and publication

©2007 American Meteorological Society or meteorological body tasked with creating and maintaining a list of extreme weather events, because many factors—such as the type of instrumentation, the site exposure, the calibration of the recording instrument, and even the frequency of measurement—are critical elements of an offi cial evaluation of a weather record. It should be noted that the private sector also maintains a wide range of observing systems and contains many users of weather records. How best to incorporate the private sector in weather record keeping is a subject that goes beyond the scope of this paper, but one whose importance we do not wish to overlook (Pielke et al. 2003). For the United States, the issue of adjudication of a weather record has led to the creation of a committee tasked with that responsibility. Th e National Oceanic and Atmospheric Administration (NOAA) established the National Climate Extremes Committee (NCEC) in 1997 “to assess the scientifi c merit of extreme meteorological/climatological events and provide a recommendation to NOAA management regarding the validity of related meteorological measurements.” Th e committee consists of three members: the chair, representing the National Climatic Data Center (NCDC); a member from the National Weather Service’s (NWS’s) Offi ce of Climate, Water, and Weather; and a representative from the American Association of State Climatologists (AASC). Th e NCEC mission statement maintains that the committee will consider certain weather elements (explicitly, temperature, snow, rain, wind, hail, and atmospheric pressure) (NCDC 2005). Th e following few additional caveats are also important:

IMPACT OF THE SOUTHERN OSCILLATION ON THE NORTH AMERICAN SOUTHWEST MONSOON

The intensity and spatial variations in the North American Southwest Monsoon are examined to determine the influence of the Southern Oscillation. Sixty-five years (1920–1984) of July and August monthly precipitation data from Arizona and New Mexico are normalized using a square root transformation, converted into z-scores, and stratified according to onset and following years for Warm Events and Cold Events of the Southern Oscillation. The results for July reveal different spatial patterns in the monsoonal precipitation for the extremes of the Southern Oscillation. Warm-Event onset years are associated with positive precipitation anomalies that decline along a northeast-to-southwest gradient across the study area whereas the Cold-Event onset years produce highest positive values in west-central Arizona and negative values throughout the eastern two-thirds of the study area. Spatial patterns for the August precipitation data do not appear to be influenced by the extremes of the Southern Oscillation. [Key w...

The Moon and El Niño

Regional climates around the world display cycles corresponding to the 18.61-year maximum lunar declination (MLD) periodicity. We suggest that these cycles are created by a relationship between MLD and El Nino / Southern Oscillation (ENSO). Both equatorial Pacific sea-surface temperature and South Pacific atmospheric pressure significantly correlate with maximum lunar declination. Low MLDs are associated with warmer equatorial Pacific sea-surface temperatures and negative values of the Southern Oscillation Index. A lunar-influenced change in the Pacific gyre circulation presents a viable physical mechanism for explaining these relationships. We suggest that the gyre is enhanced by tidal forces under high MLDs, inducing cold-water advection into the equatorial region but is restricted by the weak tidal forcing of low MLDs thereby favoring El Nino episodes. An astronomical model utilizing this relationship produces a forecast of increased non-El Nino (either La Nina or neutral) activity for the early part of this decade.

Extreme Weather: World-Record Rainfalls During Tropical Cyclone Gamede

Abstract The World Meteorological Organization (WMO) Commission for Climatology (CCl) evaluation process is applied to two extreme rainfall records occurring at Cratere Commerson on La Reunion Island during the passage of the major Tropical Cyclone (TC) Gamede for inclusion into the WMO CCl World Weather and Climate Extremes Archive. In February 2007, TC Gamede made two approaches to La Reunion Island as it traversed a rather complex path in the Indian Ocean. Gamedes main feature was massive rainfall accumulation inland, with several 3- and 4-day rainfall totals exceeding 2 m. Specifically, an extreme rainfall rate of 3,929 mm over 72 h was recorded at Cratere Commerson, well above the previous world record of 3,240 mm that had been measured at Grand-Ilet during TC Hyacinthe in 1980. In addition, the Cratere Commerson rain gauge registered a rainfall total of 4,869 mm over 4 days; also well above the previous world record. The evaluation committee found that consistent regional rainfall measurements, rel...