Number Of Summer Days Research Articles

Relationships between airborne fungal spore concentration of Cladosporium and the summer climate at two sites in Britain.

Cladosporium conidia have been shown to be important aeroallergens in many regions throughout the world, but annual spore concentrations vary considerably between years. Understanding these annual fluctuations may be of value in the clinical management of allergies. This study investigates the number of days in summer when spore concentration exceeds the allergenic threshold in relation to regional temperature and precipitation at two sites in England and Wales over 27 years. Results indicate that number of days in summer when the Cladosporium spores are above the allergenic concentration is positively correlated with regional temperature and negatively correlated with precipitation for both sites over the study period. Further analysis used a winter North Atlantic Oscillation index to explore the potential for long-range forecasting of the aeroallergen. For both spore measurement sites, a positive correlation exists between the winter North Atlantic Oscillation index and the number of days in summer above the allergenic threshold for Cladosporium spore concentration.

LONG–TERM PRECIPITATION ANALYSES FOR THE CENTRAL TEXAS BLACKLAND PRAIRIE

Continuous records of intensively monitored precipitation data are rare, but where available they provide valuable regional information on hydrologic structure design and on other water supply and water quality management and modeling issues. One such long–term precipitation record exists for the Texas Blackland Prairie region. Beginning in 1937 and continuing to the present, hydrologic data have been collected at the USDA–ARS Grassland Soil and Water Research Laboratory watershed facility near Riesel, Texas. The objectives of this article are to present long–term analyses and to publicize the availability of that precipitation database. Long–term analyses included examination of general precipitation properties, depth–duration–frequency relationships, and trends in rainfall amount and occurrence. Annual rainfall for the region averages about 890 mm, with relatively wet springs and falls and drier summer and winter months. Depth–duration–frequency results emphasize the need for engineers to use the most current and extensive data sets and/or proven relationships in the design of hydrologic structures. Several significant temporal trends that can affect water resource management were also determined. These trends include increases in October rainfall, non–spring rainfall, and the number of summer, fall, and annual rainy days. These increases, however, are offset to some degree by decreases in April rainfall, in the number of extreme events in the spring, and in the magnitude of extreme fall rain events.

Trends in exceedances of the ozone air quality standard in the continental United States, 1980–1998

In 1997, the United States National Ambient Air Quality Standard (NAAQS) for ozone was revised from a 1-h average of 0.12 parts per million (ppm) to an 8-h average of 0.08 ppm. Analysis of ozone data for the ensemble of the contiguous United States and for the period 1980–1998 shows that the average number of summer days per year in exceedance of the new standard is in the range 8–24 in the Northeast and in Texas, and 12–73 in southern California. The probability of exceedance increases with temperature and exceeds 20% in the Northeast for daily maximum temperatures above 305 K. We present the results of several different approaches to analyzing the long-term trends in the old and new standards over the continental United States from 1980 to 1998. Daily temperature data are used to resolve meteorological variability and isolate the effects of changes in anthropogenic emissions. Significant negative trends are found in the Northeast urban corridor, in the Los Angeles Basin and on the western bank of Lake Michigan. Temperature segregation enhances the detection of negative trends. Positive trends occur at isolated sites, mostly in the Southeast; a strong positive trend is found in Nashville (Tennessee). There is some evidence that, except in the Southwest, air quality improvements from the 1980s to the 1990s have leveled off in the past decade.

Inner-scale effect on irradiance variance measured for weak-to-strong atmospheric scintillation

Experimental results are described of measurements of irradiance fluctuations of laser radiation through atmospheric turbulence. Simultaneous measurements of irradiance fluctuations, inner scale, and structure parameter were made in conditions of homogeneous turbulence during a number of summer days, from very early in the morning, before sunrise, until approximately noon. During the measurements the turbulence strength varied continuously, spanning very low as well as intermediate and very high levels. We used the data collected in selected intervals, during which turbulence was stationary, to obtain plots of irradiance variance versus the structure parameter for fixed ranges of values of the inner scale. The results clearly show the effect of the inner scale. For a given value of the structure parameter larger inner scales result in larger values of irradiance variance in the regime of strong scintillation.

An Air Quality Data Analysis System for Interrelating Effects, Standards, and Needed Source Reductions: Part 6. Calculating Concentration Reductions Needed to Achieve the New National Ozone Standard

The new ozone National Ambient Air Quality Standard specifies that the expected number of days per calendar year that the 1 hour average ozone concentration can exceed 0.12 ppm must be equal to or less than 1. This paper describes a method to calculate design frequency, design concentration, and the percentage concentration reduction necessary to achieve this standard. The design frequency is once per year (1/365) if daily maximum hour ozone concentrations are available at a particular site for an equal number of days in summer (April through September) and winter (October through March). An equation is used to adjust design frequency as a function of the number of summer and winter samples available. The design concentration (the ambient concentration measured at the design frequency) needs to be reduced to 0.12 ppm. Graphical and digital methods for determining the design concentration are presented. Percentage concentration reductions needed to achieve the standard are calculated for each site which has ozone concentration data available in the National Aerometric Data Bank for at least half of the days in one summer of years 1975 through 1977. The degree of reduction calculated for the site with the highest concentrations in each county is indicated by shading on a map of the United States.

The effect of weather on the incidence of botulism in water fowl

The incidence of deaths due to botulism among water fowl in the Norfolk Broads, England, is closely related to two meteorological factors. These are the number of days in summer with a maximum air temperature of 21°C or more, and the excess of water evaporation over rainfall in the months April, May, June, July and August.