摘要:

AbstractThe purpose of this study is to investigate the relationship between the moisture condition and teleconnection patterns including the Pacific‐North American (PNA) pattern, North Atlantic Oscillation (NAO), and the El Niño‐Southern Oscillation (ENSO). The February and August Palmer's Drought Severity Index (PDSI) was used to represent the moisture condition of the cold and warm seasons in the south‐eastern USA. The teleconnection patterns were represented by the indices of PNAI, NAOI, and SOI. Composite maps for extreme values of the teleconnection indices revealed that spatial variation in the moisture condition is associated with different phases of the teleconnection patterns. Correlation analysis indicated that the PNA, NAO, and ENSO are related mostly to the subregional moisture conditions. Principal component analysis defined subregions of homogeneous moisture regimes. Then regression analysis was performed on the scores of the principal components of the February and August PDSI, using the teleconnection indices as the independent variables. The area with its cold‐season moisture condition best explained by the teleconnection patterns is central and south Florida. The teleconnection indices also explained significant portions of the variation in the cold‐season moisture condition of Mississippi and Tennessee. The teleconnection patterns in the previous autumn probably can be used to predict the moisture condition in the following winter. Compared with the cold season, the summer teleconnection patterns are less strongly related to the warm‐season moisture condition. Nevertheless, the relationships between the moisture condition and the teleconnection patterns are significant statistically. In addition, the teleconnection patterns in the previous spring offered some explanations to the spatial patterns in the warm‐season moisture condition

ISSN:0899-8418    

DOI:10.1002/joc.3370140902

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractChanges in total solar irradiance can be linked to changes in regional precipitation. A possible mechanism responsible for this linkage begins with the absorption of varying amounts of solar energy by the tropical oceans, which creates ocean temperature anomalies. These anomalies are then transported by major ocean currents to locations where the stored energy is released into the atmosphere, thereby altering atmospheric pressure and moisture patterns, which can ultimately affect regional precipitation.Correlation coefficients between annual differences in empirically modelled solar‐irradiance variations and annual State‐divisional precipitation in the USA for the period 1950–1988 were computed with lag times of 0 to 7 years. The most significant correlations occur in the Pacific North‐west, with a lag time of 4 years, which is approximately equal to the travel time of water within the Pacific gyre from the western tropical Pacific Ocean to the Gulf of Alaska. Precipitation in the Desert South‐west correlates significantly with solar irradiance lagged 3 and 5 years, which suggests a link with ocean‐water temperature anomalies transported by the Equatorial Counter Current as well as the North Pacific gyre. With the correlations obtained, droughts coincide with periods of negative irradiance differences (dry high‐pressure development), and wet periods coincide with periods of positive differences (moist low‐pressu

ISSN:0899-8418    

DOI:10.1002/joc.3370140903

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractA sensitivity analysis of the frequency of extreme precipitation events is performed. Extreme events in the form of total precipitation (e.g. over a month or season) exceeding a relatively large threshold (i.e. extremely wet conditions) or falling below a relatively small threshold (i.e. extremely dry conditions) are treated. To allow for the positive skewness of the distribution of total precipitation, a power transformation to normality is used. The relative sensitivities of extreme precipitation events to the median and to the scale parameter of this distribution are examined. It is shown that these relative sensitivities are both generally greater the more extreme the event. Moreover, the relative sensitivity to the scale is greater than that corresponding to the median for extreme wet events, whereas the opposite is true for extreme dry events. These theoretical results are illustrated through use of a network of precipitation observations in Spain.

ISSN:0899-8418    

DOI:10.1002/joc.3370140904

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractTwo relatively neglected aspects of climatic temperature variability are mean interdiurnal temperature variability (MITV), and the lag of maximum and minimum temperature behind their respective solstices. After determining the length of record to attain stability for the former, and the dates (of the year) on which temperatures are a maximum and minimum, these parameters are mapped for North America. For MITV there is a general association with continentality and the location of the surface polar front zone; the lag patterns bear only a slight resemblance to continentality.

ISSN:0899-8418    

DOI:10.1002/joc.3370140905

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe Markov chain properties of daily precipitation occurrence, namely, the dependency of the daily precipitation on that of the previous day, are studied based on the daily precipitation data for 30 years (1956–1985) at 14 stations in South Korea. The daily precipitation data at each station were classified into the wet and dry state, and transition probabilities between daily precipitation of two successive days were computed. Then the Markov chain properties and various aspects of daily precipitation occurrence from the Markov chain properties were investigated. The results are as follows: the transition probability of two successive wet days for 30 years at the 14 stations is 0.51, and the statistical tests show that the transitions of daily precipitation occurrence in South Korea can have the Markov chain property and be stationary in time, except at Ullung‐do, Seoul, Kangnung, and Mokpo, but heterogeneous in space. Then‐step Markov chain analysis shows that the ‘memory’ of the daily precipitation occurrences at 14 stations remains about 2–3 days. The weather cycle i

ISSN:0899-8418    

DOI:10.1002/joc.3370140906

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractSunshine duration fluctuation in this century is studied from annual values for 26 stations in central and south‐eastern Europe. Possible sources of inhomogeneity are identified: ageing of the glass ball in the sunshine recorder, changes in instruments, the recording tape and its evaluation, and location of the station, and exposure to air pollution. Long‐term changes of annual sunshine duration are presented using a smoothed Gauss filter and principal component analysis. The main feature of sunshine duration fluctuation in this century is its sharp decrease after a maximum at the end of the 1940s. Principal component 1 shows, with small exceptions, positive loadings for the year and its seasons (for the period of 1931–1985). Principal component 2 divides the region studied into two parts, with positive loadings in the western and northern parts of central Europe and negative loadings over the rest of area analysed. A contradictory situation occurs only in autumn. Statistically significant cycles occur at intervals of about 2.3–2.4 years (western Germany), 3 years (Greece), 3.5–3.7 years (central Europe and Bucharest) and 3.7–4.0 years (Bulgaria). Some of the stations used indicate longer cycles (44–110 years). Comparison of coldest (1901–1920) and warmest (1934–1953) 20–year periods in the Northern Hemisphere shows for the warmest period an important increase in sunshine duration, with the exception of Athens and Bucharest and some other stations in winter. In the warmer period sunshine duration variability is generally higher in spring and winter and less i

ISSN:0899-8418    

DOI:10.1002/joc.3370140907

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractMean monthly air temperatures in Cracow for the period 1826–1990 were used. The temperatures of the coldest (Tlow) the warmest (Thigh) periods of the year, and mean annual temperatures (Ta), were calculated. The persistence of temperatures was examined using the correlation coefficients between monthly temperatures in succeeding months. A significant temperature persistence was found for a cold season (December‐March) and also for the summer (July‐August). Long‐term fluctuations were analysed by means of 20‐year and 30‐year running mean values and the positive and negative squared deviations of moving 20‐year subperiods. Two warm stages were found. One at the beginning of the present century, the second at the end of the period analysed. The first warm phase was connected with a decrease in the degree of continentality. Warm phases were also linked with a decrease in the temperature variability.The spectrum and the moving spectrum in 40‐year subperiods of monthly and annual temperature records were calculated. An 8‐year period was found inTlow,Ta, and in the monthly series of the cold season, and 4‐ and 5‐year periods were found inThighand in the monthly series of the warm season.By comparing the temperature in Cracow with that at the neighbouring stations of Wieliczka, Bochnia, and Tarnów, it was found that the difference in annual means increased from −0.3°C at the end of the previous century to 1.0°C in the last two decades. About 0.5°C of this increase occurred in the last 40‐year period of abrupt expansion and industrial

ISSN:0899-8418    

DOI:10.1002/joc.3370140908

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractCharacteristics of weather types obtained from a Davis and Kalkstein classification process can depend on a variety of factors. One of them is the number of components retained after principal component analysis (PCA) of the original data. The classification algorithm itself and the number of elements to be classified also play important roles in the final results. The main objective of the present paper is to describe a methodology leading to a deduction of the minimum sample size that must be considered in order to obtain a reliable synoptic weather type classification. Some rules related to the number of factors to be retained after a PCA and the optimal number of groups of our classification procedure are discussed. Finally, the main features of the winter weather types obtained from Barcelona Airport data are briefly presented.

ISSN:0899-8418    

DOI:10.1002/joc.3370140909

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

ISSN:0899-8418    

DOI:10.1002/joc.3370140910

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

ISSN:0899-8418    

DOI:10.1002/joc.3370140912

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY