Relating meteorological variables and trends in motor vehicle emissions to monthly urban carbon monoxide concentrations

A model which quantifies the relationship between the monthly time series for CO emissions, the monthly time series in ambient CO concentration, and meteorologically driven dispersion was developed. Fifteen cities representing a wide range of geographical and climatic conditions were selected. An eight-year time series (1984–1991 inclusive) of monthly averaged data were examined in each city. A new method of handling missing ambient concentration values which is designed to calculate city-wide average concentrations that follow the trend seen at individual monitor sites is presented. This method is general and can be used in other applications involving missing data. The model uses emissions estimates along with two meteorological variables (wind speed and mixing height) to estimate monthly averages of ambient air pollution concentrations. The model is shown to have a wide range of applicability; it works equally well for a wide range of cities that have very different temporal CO distributions. The model is suited for assessing long-term trends in ambient air pollutants and can also be used for estimating seasonal variations in concentration, estimation of trends in emissions, and for filling in gaps in the ambient concentration record.     

城市发展对室内外气温影响初探

本文以昆明市为研究对象。昆明地区受全球气候变暖影响年平均气温约升高 0 4 7℃ /a ;由于城市面积扩大导致昆明的室内外气温均升高 ,城市增温效应在 1 -4月较大 ,5-1 2月较小 ;在相同月份 ,平均室内气温的增温率均大于平均气温 ;城市增温效应与城市建成区面积、城市人口均有较好地相关关系。城市建成区面积增加对平均气温的影响较大 ;而城市人口增加对平均室内气温的影响较大。     

西安咸阳高速公路大气能见度变化特征及影响因子分析

利用西安咸阳高速公路交通气象自动观测站网2013年8月—2015年4月共21个月的交通气象实时观测资料,对西安咸阳高速路段大气能见度变化特征及其主要气象影响因子进行了分析。结果表明:汉城收费站、渭河大桥北站能见度的月际变化均呈双峰双谷型分布;机场收费站能见度呈多峰型波动变化。3站能见度平均值按照逐渐靠近机场的顺序依次下降。对3站而言,14:00时大气能见度最好;能见度最低值出现的时刻因站而异。对3站而言,能见度与气温均呈明显的U型二次多项式相关;与相对湿度呈多项式型负相关;与风速之间存在一定的多项式相关性,但相关性较弱。受到机场较强的人为交通源排放影响,随着与西安咸阳国际机场距离的缩短,3站能见度与气温、相对湿度及风速之间的相关性依次递减。     

EVALUATION OF PROBABILITY DENSITY FUNCTIONS IN PRECIPITATION MODELS FOR THE PACIFIC NORTHWEST1

ABSTRACT: Recent work has found that a one-parameter Weibull model of wet day precipitation amount based on the Weibull distribution provides a better fit to historical daily precipitation data for eastern U.S. sites than other one-parameter models. The general two-parameter Weibull distribution was compared in this study to other widely used distributions for describing the distribution of daily precipitation event sizes at 99 sites from the U.S. Pacific Northwest. Surprisingly little performance was sacrificed by reducing the two-parameter Weibull to a single-parameter distribution. Advantages of the single-parameter model included requiring only the mean wet day precipitation amount for calibration, invertibility for simulation purposes, and ease of analytical manipulation. The fit of the single-parameter Weibull to the 99 stations included in this study was significantly better than other single-parameter models tested, and performed as well as the widely endorsed, more cumbersome, two-parameter gamma model. Both the one-and two-parameter Weibull distributions are shown to have b-moments that are consistent with historical precipitation data, while the ratio of b-skew and b-variance in the gamma model is inconsistent with the historical recerd by this measure. In addition, it was found that the two-parameter gamma distribution was better fit using the method of moments estimators than maximum likelihood estimates. These findings suggested that the distribution in precipitation among sites in the Pacific Northwest with dramatically different settings are nearly identical if expressed in proportion to the mean site event size.     

REGIONAL RAINFALL INTENSITY-DURATION-FREQUENCY CURVES FOR PENNSYLVANIA1

ABSTRACT: A statistical analysis of all available continuous hourly and 15-minute duration rainfall records for Pennsylvania was performed to develop an updated procedure to estimate design storms. As a resuit of this study, Pennsylvania was divided into five homogeneous rainfall regions and a set of rainfall intensity-duration curves developed for each region, for return periods of 1 to 100 years and durations ranging from 5 minutes to 24 hours. The PDT-IDF curves were judged to be a better representation of Pennsylvania rainfall than the nationwide TP-40 maps, particularly for storm events of 10-years and lower return periods. The average time distribution of 24-hour storms in Pennsylvania was found to be well represented by the SCS Type II distribution. The Corps of Engineers SPS 24-hour distribution was found to differ appreciably from both the SCS Type H and the Pennsylvania 24-hour storm distribution. For storm durations between 15 and 90 minutes the standard Yarnell intensity-duration curves closely resemble Pennsylvania storm distributions.     

乌鲁木齐-奎屯高等级公路沿线污染气象分析

就乌鲁木齐－奎屯高等级公路沿线的污染气象条件进行分析，为研究道路二侧汽车尾气污染提供必要的参数。     

基于EOF/SVD的2018年湖北省臭氧特征及其高值与气象要素关系研究

基于湖北省2018年4-10月臭氧、温度和相对湿度逐小时监测数据以及50 m风场逐小时再分析数据,采用经验正交函数(EOF)和奇异值分解(SVD)方法,分析了2018年湖北省臭氧特征及其高值与气象要素关系。结果表明:湖北省臭氧日最大8 h浓度距平呈现以武汉为正值中心、自鄂东向鄂西递减的主要空间分布型;15:00臭氧与温度呈现较好的正相关关系,以随州、襄阳及其周边最为明显;与14:00相对湿度呈现很好的负相关关系,以孝感、随州、荆门及其周边最为明显;襄阳西部和十堰北部地区15:00 50 m风场的纬向分量对本地臭氧高值有一定影响,武汉北部、黄冈北部以及孝感东部等地15:00 50 m风场的经向分量对本地臭氧高值影响较大。     

PREDICTING THE SUMMER TEMPERATURE OF SMALL STREAMS IN SOUTHWESTERN WISCONSIN1

ABSTRACT: One of the biggest challenges in managing cold water streams in the Midwest is understanding how stream temperature is controlled by the complex interactions among meteorologic processes, channel geometry, and ground water inflow. Inflow of cold ground water, shade provided by riparian vegetation, and channel width are the most important factors controlling summer stream temperatures. A simple screening model was used to quantitatively evaluate the importance of these factors and guide management decisions. The model uses an analytical solution to the heat transport equation to predict steady‐state temperature throughout a stream reach. The model matches field data from four streams in southwestern Wisconsin quite well (typically within 1°C) and helps explain the observed warming and cooling trends along each stream reach. The distribution of ground water inflow throughout a stream reach has an important influence on stream temperature, and springs are especially effective at providing thermal refuge for fish. Although simple, this model provides insight into the importance of ground water and the impact different management strategies, such as planting trees to increase shade, may have on summer stream temperature.     

WATER LEVEL FLUCTUATIONS IN AN URBAN POND: CLIMATIC OR ANTHROPOGENIC IMPACT?1

ABSTRACT: In 1996, the Illinois State Geological Survey began an investigation of fluctuating water levels in a pond in Cary, Illinois. The cause of the fluctuations appeared to be ground water discharge into a storm sewer recently installed by the Illinois Department of Transportation. However, analysis of climatic data provided an equally likely explanation of the fluctuations. Distinguishing the effect of climatic variations from the effect of the storm sewer was hampered by the lack of antecedent ground water and surface water data. In similar settings, it is recommended that ground water and surface water data be collected prior to initiating any infrastructure improvements.     

MESOSCALE ATMOSPHERIC 2XCO2 CLIMATE CHANGE SIMULATION APPLIED TO AN OREGON WATERSHED1

ABSTRACT: A 2xCO2 climate and runoff in the Upper Deschutes Basin in central Oregon is simulated using a mesoscale atmospheric model and a watershed model that incorporates spatial variability of the runoff process. A nine‐year control climate monthly time series provides a benchmark for assessing changes related to a warmer and wetter 2xCO2 climate. Potential evapotranspiration is increased by 23 percent and snow water equivalent is reduced by 59 percent in the 2xCO2 climate. Annual runoff increases by 23 percent, while November runoff increases by 55 percent. The average maximum monthly runoff is in May for both the control climate and 2xCO2 climate, but in five of the nine years the monthly maximum runoff for the 2xCO2 climate occurs two to five months earlier than for the control climate. The minimum runoff month is one to five months earlier in the 2xCO2 climate in seven of the nine years, and the month of average minimum runoff is March in the control climate and November in the 2xCO2 climate. Since precipitation is greatest in December in both the control climate and 2xCO2 climate, the earlier maximum and minimum runoff for a 2xCO2 climate indicates greater watershed sensitivity to temperature than to precipitation.