Changes in climate and levels of lake Michigan: shoreline impacts at Chicago

This study concerns effects along the Illinois shoreline resulting from the record-low levels of Lake Michigan during 1964–65, and the potential impacts of future low water levels at Chicago resulting from potential climate changes. The low lake levels of the 1960s did not cause major impacts at Chicago when they occurred. The two major impacts discerned (damage to shoreline protection structures and the encroachment of structures onto areas too close to the lake) resulted from a sequence of low-water levels followed by high-water levels a few years later. Climate scenarios, derived from general circulation models (GCMs) and extreme historical precipitation values, were used in a basin hydrologic model to determine potential future lake levels. Possible impacts were then estimated by 29 lakeshore experts. If the average lake level were reduced 1.0 m during the next 50 yr, shoreline impacts would not be severe and cost about $ 100 million. Many of the adjustment costs could be offset by normal maintenance and replacement costs. If the average lake level was reduced more than 1.5 m during the next 50 yr, very sizable economic impacts would occur, costing between $3 and $35 billion (1988 dollars). Some of the adjustment cost could be offset by normal replacement costs, particularly if a master plan for changing affected facilities were implemented in advance. The type of climate change and degree of lakelevel change will greatly affect the severity of the effects at Chicago.     

充分利用数据库资料提高雷雨预报准确率

2000年7月17日午后及晚上双流机场产生了两次强雨天气过程，机场预报员成功地对上述过程做出准确以预报；本文就当日的天气过程进行了较为详细地分析，进一步总结出民航气象数据库WAFS（世界区域预报系统的简称，以下同）产品500hPa高空风既流场形势预预告图对近两年来双流机场多起夏季雷雨天气过程成功预测所起的作用，为双流机场夏季雷雨的预报提供了一个着眼点。     

充分利用数据库资料提高雷雨预报准确率

2000年7月17日午后及晚上双流机场产生了两次强雷 雨天气过程，机场 预报员成功地对上述过程做出准确预报；本文就当日的天气过程进行了较为详细的分析，进 一步总结出民航气象数据库WAFS(世界区域预报系统的简称，以下同)产品500hPa高空风既流 场形势预告图对近两年来双流机场多起夏季雷雨天气过程成功预测所起的作用，为双流机场 夏季雷雨的预报提供了一个着眼点。     

A simple model for describing the heat balance of a shallow lake with application to Lake Chad

A model is described allowing the computation of a shallow lake's surface temperature as a function of the meteorological conditions of the surroundings. An equilibrium temperature with no heat flux through the surface is defined. The daily cycle of the equilibrium temperature permits computation of the average and the amplitude of the lake's temperature in the form of a simple sine wave. The computed values are compared with satellite measurements of the surface temperature and good agreement is achieved. When the computed surface temperature is applied, the values of the fluxes of latent and sensible heat are in good agreement with observational data.     

Trend analysis of precipitation time series in Greece and their relationship with circulation using surface and satellite data: 1955–2001

Summary In this study, the trends of annual and seasonal precipitation time series were examined on the basis of measurements of 22 surface stations in Greece for the period 1955–2001, and satellite data during the period 1980–2001. For this purpose, two statistical tests based on the least square method and one based on the Mann-Kendall test, which is also capable of detecting the starting year of possible climatic discontinuities or changes, are applied. Greece, in general, presents a clear significant downward trend in annual precipitation for the period 1955–2001, which is determined by the respective decreasing trend in winter precipitation. Both winter and annual series exhibit a downward trend with a starting year being 1984. Satellite-derived precipitation time series could be an alternative means for diagnosing the variability of precipitation in Greece and detecting trends provided that they have been adjusted by surface measurements in the wider area of interest. The relationship between precipitation variability in Greece and atmospheric circulation was also examined using correlation analysis with three circulation indices: the well-known North Atlantic Oscillation Index (NAOI), a Mediterranean Oscillation Index (MOI) and a new Mediterranean Circulation Index (MCI). NAOI is the index that presented the most interesting correlation with winter, summer and annual precipitation in Greece, whereas the MOI and MCI were found to explain a significant proportion of annual and summer precipitation variability, respectively. The observed downward trend in winter and annual precipitation in Greece is linked mainly to a rising trend in the hemispheric circulation modes of the NAO, which are connected with the Mediterranean Oscillation Index.     

Trend analysis of air temperature time series in Greece and their relationship with circulation using surface and satellite data: recent trends and an update to 2013

Theoretical and Applied Climatology - In this paper, the surface and lower tropospheric temperature trends in Greece and their relationship to the atmospheric circulation for the period...