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1.
Anomalies of mean air temperature of 12 consecutive months were detected recently at a number of spatial scales: from local via national and continental, to hemispheric. At all these spatial scales, pre-2007 records were exceeded by considerable margins. The recent rise in the mean temperature of 12 consecutive months at several scales has remained largely unnoticed, because the 12-month means are seldom analyzed. Broad attention is typically focused on monthly, seasonal and annual temperatures. Analysis of shifted 12-month periods helps spot peculiar 12-month episodes with remarkable temperature anomalies that do not coincide with a calendar year. Introducing 12-month running mean temperatures into the global warming debate can prove useful.  相似文献   

2.
ＡＳｔｕｄｙｏｆＨｅａｖｙＲａｉｎｆａｌｌｏｆ８－１０Ｊｕｎｅ，１９９１ｏｖｅｒＭａｈａｒａｓｈｔｒａ，ＩｎｄｉａＡ．Ｋ．Ｋｕｌｋａｒｎｉ，Ｂ．Ｎ．ＭａｎｄａｌａｎｄＲ．Ｂ．ＳａｎｇａｍＡＳｔｕｄｙｏｆＨｅａｖｙＲａｉｎｆａｌｌｏｆ８－１０Ｊｕｎｅ，...  相似文献   

3.
This paper deals with direct calculations of the radiation-equilibrium temperature profile in the Earth’s atmosphere from experimental spectroscopic data. The calculations are made for its present composition and for the modified ones, when concentration of a gas, namely, one of carbon dioxide CO2, methane CH4, nitrous oxide N2O or water vapor H2O is changed. Calculations were carried out with one-dimensional (horizontally homogeneous) radiation model proceeding from the values of absorption coefficients of atmospheric layers estimated from actual data. Calculations are carried out for small disturbances of the said gases’concentrations. Approximate estimates of large disturbance were made for the cases of total withdrawal of concrete gas from the atmosphere or, on the contrary, of large increase in its concentration.  相似文献   

4.
Empirical equations relating runoff,maximum river stageand peak flow to rainfall were developed for the Tao riverdrainage basin at Li Jia Cun.A basin recession curve wasderived and a frequency analysis of extreme flood events wasconducted.Results showed that storm runoff was highlycorrelated with rainfall.However,maximum river stage andpeak flow were not as well correlated with rainfall.It wasfound necessary to separate rainfall into stratiform andconvective types.The magnitudes of the once-in-50 year,once-in-100 year and once-in-200 year events,calculated by thelog Pearson type Ⅲ distribution were closely equal to thoseestimated from a log-probability graph.Recommendations forimproving the predictive ability of the empirical equations arepresented.  相似文献   

5.
《Climate Policy》2002,2(1):124-126
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6.
Paleoclimate modelling is one of the core topics in the Past Global Changes project under the International Geosphere-Biosphere Programme and has received much attention worldwide in recent decades. Here we summarize the research on the Paleoclimate modeling, including the Holocene, Last Glacial Maximum, and pre-Quaternary climate intervals or events performed at the Institute of Atmospheric Physics under the Chinese Academy of Sciences (IAP/CAS) for over one decade. As an attempt to review these academic activities, we emphasize that vegetation and ocean feedbacks can amplify East Asian climate response to the Earth’s orbital parameters and atmospheric CO2 concentration at the mid-Holocene. At the Last Glacial Maximum, additional cooling in interior China is caused by the feedback effects of East Asian vegetation and the ice sheet over the Tibetan Plateau, and the regional climate model RegCM2 generally reduces data-model discrepancies in East Asia. The simulated mid-Pliocene climate is characterized by warmer and drier conditions as well as significantly weakened summer and winter monsoon systems in interior China. On a tectonic timescale, both the Tibetan Plateau uplift and the Paratethys Sea retreat play important roles in the formation of East Asian monsoon-dominant environmental pattern during the Cenozoic.  相似文献   

7.
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8.
The rate coefficients for the reaction between atomic chlorine and a number of naturally occurring species have been measured at ambient temperature and atmospheric pressure using the relative rate technique. The values obtained were (4.0 ± 0.8) × 10-10, (2.1 ± 0.5) × 10-10, (3.2 ± 0.5) × 10-10, and (4.9 ± 0.5) × 10-10 cm3 molecule-1 s-1, for reactions with isoprene, methyl vinyl ketone, methacrolein and 3-carene, respectively. The value obtained for isoprene compares favourably with previously reported values. No values have been reported to date for the rate constants of the other reactions.  相似文献   

9.
Precipitation causes several short- and long-term effects on wind-induced surface erodibility and subsequent dust emission. Among the principal effects considered by this paper are soil moisture, soil crusts, and vegetation. A quantitative method is developed to assess these effects using differences between the potential and the actual amounts of dust emitted from dust sources as inferred from surface meteorological measurements obtained downwind from those sources. The results of this assessment must be interpreted with caution, however, when the size and location of dust sources are unknown.Using meteorological data recorded near Yuma, Arizona at the Yuma Marine Corps Air Station (YMCAS), the method is applied to calculate the potential and actual amounts of dust emitted from upwind dust sources during the spring and fall/winter seasons between January 1, 1981 and May 31, 1988. (Spring is considered to be the period between February 1 and May 31; fall/winter, between October 1 and January 31.) Because summer precipitation is intermittent and wind patterns are localized, summer meteorological data are not used to evaluate regional correlations between precipitation and dust storms. For the period between 1981 and 1988, a correlation of -0.60 was found between fall/winter precipitation and the actual amount of dust emitted from sources upwind of YMCAS during the following spring. A particularly strong reduction in dust emission was noted during the springs of 1983 and 1984 following the start of an El Nino event in fall/winter 1982. Photographs taken at a geological and meteorological data-collection (Geomet) site, located in the natural desert 25 km southeast of YMCAS, show a correspondence between increased antecedent precipitation recorded at the site and increased vegetation. Whereas the annual precipitation totals at YMCAS and the Geomet site from the beginning of 1982 through 1984 are high, their seasonal totals, especially during the fall/winter seasons, are disparate. This fall/winter precipitation disparity may account for evidence suggesting that significant vegetation growth occurred at dust sources upwind of YMCAS by spring 1983, but that such growth did not occur at the Geomet site until fall/ winter of 1983. Spatial inhomogeneity in fall/winter precipitation probably contributed to the relatively low correlation (-0.60) between fall/winter precipitation recorded at YMCAS and the actual amount of dust emitted from upwind sources during the following spring.  相似文献   

10.
Using a regional climate model MM5 nested to an atmospheric global climate model CCM3, a series of simulations and sensitivity experiments have been performed to investigate the relative LGM climate response to changes of land-sea distribution, vegetation, and large-scale circulation background over China.Model results show that compared with the present climate, the fluctuations of sea-land distribution in eastern Asia during the LGM result in the temperature decrease in winter and increase in summer. It has significant impact on the temperature and precipitation in the east coastal region of China. The impact on precipitation in the east coastal region of China is the most significant one, with 25%-50% decrease in the total precipitation change during the LGM. On the other hand, the changes in sea-land distribution have less influence on the climate of inland and western part of China. During the LGM, significant changes in vegetation result in temperature alternating with winter increase and summer decrease, but differences in the annual mean temperature are minor. During the LGM, the global climate, i.e., the large-scale circulation background has changed significantly. These changes have significant influences on temperature and precipitation over China. They result in considerable temperature decreases in this area, and direct the primary patterns and characteristics of temperature changes. Results display that, northeastern China has the greatest temperature decrease, and the temperature decrease in the Tibetan Plateau is larger than in the eastern part of China located at the same latitude. Moreover, the change of large-scale circulation background also controls the pattern of precipitation change. Results also show that, most of the changes in precipitation over western and northeastern parts of China are the consequences of changing large-scale circulation background, of which 50%-75% of precipitation changes over northern and eastern China are the results of changes in large-scale circulation background. Over China, the LGM climate responses to different mechanisms in order of strength from strong to weak are, the large-scale circulation pattern, sea-land distribution, vegetation, CO2 concentration, and earth orbital parameters.  相似文献   

11.
Forecasting austral summer rainfall in southern Africa is hampered by a lack of long-term instrumental data. This paper extends the historical record for the subcontinent by presenting the first extensive 19th century climate history for Lesotho derived from documentary evidence. The data sources included unpublished English-, French- and Sesotho-language materials archived in Lesotho, South Africa and the UK. These included letters, journals and reports written by missionaries and colonial authorities, which were supplemented by newspapers, diaries, travelogues and other historical sources. Each source was read in chronological order, with any climate information recorded verbatim. Observations were classified into five categories (Very Wet, Relatively Wet, ‘Normal’, Relatively Dry, and Very Dry) based upon the predominant documented climate during each ‘rain-year’ (July to June). The latter portion of the chronology was then compared for accuracy against available instrumental precipitation records from Maseru (1886–1900). The results yield a semi-continuous record of climate information from 1824 to 1900. Data are restricted to lowland areas, but reveal drought episodes in 1833–34, 1841–42, 1845–47, 1848–51, 1858–63, 1865–69, 1876–80, 1882–85 and 1895–99 (the most severe drought years being 1850–51 and 1862–63) and wet periods or floods in 1835–36, 1838–41, 1847–48, 1854–56, 1863–65, 1873–75, 1880–81, 1885–86 and 1890–94. The rainfall chronology is compared with similar records for South Africa, Botswana and Zimbabwe. Linkages to possible forcing mechanisms, including ENSO teleconnections and historical coral-derived southwest Indian Ocean sea surface temperature variations are also explored.  相似文献   

12.
Gao  Feng  Chen  Xiaoling  Yang  Wenfu  Wang  Wenwen  Shi  Lijiang  Zhang  Xiaolong  Liu  Yaomeng  Tian  Yaofei 《Theoretical and Applied Climatology》2022,148(3-4):955-966
Theoretical and Applied Climatology - Under the background of global warming, an analysis of the trend and variability of rainfall time series on various timescales is very important for...  相似文献   

13.
The absorption properties of the water vapor continuum and a number of weak bands for H2O, O2, CO2, CO, N2O, CH4, and O3 in the solar spectrum are incorporated into the Fu-Liou radiation parameterization program by using the correlated k-distribution method (CKD) for the sorting of absorption lines. The overlap absorption of the H2O lines and the H2O continuum (2500-14500 cm^-1) are treated by taking the two gases as a single-mixture gas in transmittance calculations. Furthermore, in order to optimize the computation efforts, CO2 and CH4 in the spectral region 2850-5250 cm^-1 are taken as a new singlemixture gas as well. For overlap involving other absorption lines in the Fu-Liou spectral bands, the authors adopt the multiplication rule for transmittance computations under which the absorption spectra for two gases are assumed to be uncorrelated. Compared to the line-by-line (LBL) computation, it is shown that the errors in fluxes introduced by these two approaches within the context of the CKD method are small and less than 0.48% for the H20 line and continuum in the 2500-14500 cm^-1 solar spectral region, -1% for H2O (line) H2O (continuum) CO2 CH4 in the spectral region 2850-5250 cm^-1, and -1.5% for H2O (line) H2O (continuum) O2 in the 7700-14500 cm^-1 spectral region. Analysis also demonstrates that the multiplication rule over a spectral interval as wide as 6800 cm^-1 can produce acceptable errors with a maximum percentage value of about 2% in reference to the LBL calculation. Addition of the preceding gases increases the absorption of solar radiation under all sky conditions. For clear sky, the increase in instantaneous solar absorption is about 9%-13% (-12 W m^-2) among which the H20 continuum produces the largest increase, while the contributions from O2 and CO2 rank second and third, respectively. In cloudy sky, the addition of absorption amounts to about 6-9 W m^-2. The new, improved program with the incorporation of the preceding gases produces a smaller solar absorption in clouds due to the reduced solar flux reaching the cloud top.  相似文献   

14.
Using a regional climate model MM5 nested to an atmospheric global climate model CCM3, a series of simulations and sensitivity experiments have been performed to investigate the relative LGM climate response to changes of land-sea distribution, vegetation, and large-scale circulation background over China. Model results show that compared with the present climate, the fluctuations of sea-land distribution in eastern Asia during the LGM result in the temperature decrease in winter and increase in summer. It has significant impact on the temperature and precipitation in the east coastal region of China. The impact on precipitation in the east coastal region of China is the most significant one, with 25%-50% decrease in the total precipitation change during the LGM. On the other hand, the changes in sea-land distribution have less influence on the climate of inland and western part of China. During the LGM, significant changes in vegetation result in temperature alternating with winter increase and summer decrease, but differences in the annual mean temperature are minor. During the LGM, the global climate, i.e., the large-scale circulation background has changed significantly. These changes have significant influences on temperature and precipitation over China. They result in considerable temperature decreases in this area, and direct the primary patterns and characteristics of temperature changes. Results display that, northeastern China has the greatest temperature decrease, and the temperature decrease in the Tibetan Plateau is larger than in the eastern part of China located at the same latitude. Moreover, the change of large-scale circulation background also controls the pattern of precipitation change. Results also show that, most of the changes in precipitation over western and northeastern parts of China are the consequences of changing large-scale circulation background, of which 50%-75% of precipitation changes over northern and eastern China are the results of changes in large-scale circulation backgrou  相似文献   

15.
Having been in use at Hohenpeissenberg from 1781–1841, the Palatina thermometer was found to suffer from a positive bias of 0.5°R (or 0.63°C) as discovered by Lamont following a re-calibration made in 1842. The main reason was due to the composition of the glass used during the early instrumental period. Glass of this period tended to contract over many years due to thermal aftereffects, resulting in a gradual rise of the freezing point position in consequence of the shrinking bulb forming the mercury reservoir. While the problem of the gradually rising zero point was recognised relatively early, the reason was attributed to wrong causes. Around 1880, scientists recognised that the chemical composition of glass might be responsible for the drift of the zero point. New glass types were developed which were free from such effects. Although these facts became known, no correction was applied to the Hohenpeissenberg temperature series when in 1981, the complete 200-year series was published. Most probably this bias is also relevant for other stations, at least those of the network of the Societas Meteorologica Palatina that were supplied with thermometers manufactured in Mannheim. Another problem originates from the different observing times for the period 1879–1900, which were set to 0800, 1400 and 2000 hours instead of 0700, 1400 and 2100 hours before and afterwards. In addition, a new formula to calculate the daily mean was established resulting in the temperature being too low by 0.5°C in that period. The overall trend changes after application of the two necessary corrections. There remain two biases that cannot be quantified without a major detailed study being made: (1) At the start of the observations, the window of the observation room was always kept “open during dry weather”. It is not known how long this practice was remained in use. (2) Lamont also employed an easily melting glass to construct his thermometers which in use between 1841 and 1878. An analysis of the glass composition seems to be necessary to find out whether it also suffered from a rising freezing point. Lamont replaced the Hohenpeissenberg thermometer in 1842 by a new instrument produced in his own workshop. One still existing Lamont thermometer, but not that one of Hohenpeissenberg, was re-calibrated and the zero point found to have lowered by ?1.4°C. Since the opposite drift had been expected and the original Lamont-type Hohenpeissenberg thermometer is no longer available, no correction is justified for the period in which this thermometer was in use.  相似文献   

16.
The absorption properties of the water vapor continuum and a number of weak bands for H2O, O2, CO2, CO, N2O, CH4, and O3 in the solar spectrum are incorporated into the Fu-Liou radiation parameterization program by using the correlated k-distribution method (CKD) for the sorting of absorption lines. The overlap absorption of the H2O lines and the H2O continuum (2500-14500 cm-1) are treated by taking the two gases as a single-mixture gas in transmittance calculations. Furthermore, in order to optimize the computation efforts, CO2 and CH4 in the spectral region 2850-5250 cm-1 are taken as a new single-mixture gas as well. For overlap involving other absorption lines in the Fu-Liou spectral bands, the authors adopt the multiplication rule for transmittance computations under which the absorption spectra for two gases are assumed to be uncorrelated. Compared to the line-by-line (LBL) computation, it is shown that the errors in fluxes introduced by these two approaches within the context of the CKD method are small and less than 0.48% for the H2O line and continuum in the 2500-14500 cm-1 solar spectral region, -1% for H2O (line) H2O (continuum) CO2 CH4 in the spectral region 2850-5250 cm-1, and -1.5% for H2O (line) H2O (continuum) O2 in the 7700-14500 cm-1 spectral region. Analysis also demonstrates that the multiplication rule over a spectral interval as wide as 6800 cm-1 can produce acceptable errors with a maximum percentage value of about 2% in reference to the LBL calculation. Addition of the preceding gases increases the absorption of solar radiation under all sky conditions. For clear sky, the increase in instantaneous solar absorption is about 9%-13% (~12 W m~2) among which the H2O continuum produces the largest increase, while the contributions from O2 and CO2 rank second and third, respectively. In cloudy sky, the addition of absorption amounts to about 6-9 W m-2. The new, improved program with the incorporation of the preceding gases produces a smaller solar absorption in clouds due to the reduced solar flux reaching the cloud top.  相似文献   

17.
Formaldehyde (HCHO), acetaldehyde (CH3CHO) and acetone (CH3COCH3) were measured at Wanqingsha (WQS) in south China during November-December 2008–2010. Carbonyl compound pollution characteristics under the influence of the financial crisis (FC) were studied. Atmospheric carbonyl compound concentrations in the 2008 and 2009 sampling periods were affected by the 2008 FC. The industrial downturn plus the high closing down number of the small enterprises with limited emission treatment during the FC played an important role in the reduction of the industry-related CH3CHO and CH3COCH3. In 2010, the recovery of industrial activities occurred, but affected by traffic restriction enforcement in Guangzhou over the Asian Games period, HCHO concentration (daytime 7.59?±?2.59 μg m?3) was lower than expectation. Carbonyl compounds in WQS site were highly influenced by regional pollution transport from different upwind urban cities and industrial districts in the north-northwest to northeast wind sector in winter. Also, the interaction of the winter monsoon with the warm ocean along the coastline as well as day and night boundary layer mixing height variation affected carbonyl compound concentrations in WQS. The daytime mean dry deposition losses of HCHO and CH3CHO were first time model-estimated for 2009 and 2010. For loss of HCHO in the early afternoon, photolysis was the dominant sink, followed by dry deposition and removal by OH radical (?OH), while for CH3CHO, dry deposition was dominant. For the gain of HCHO and CH3CHO, the production rates during early afternoon in 2009 and 2010 were estimated by an indirect approach.  相似文献   

18.
The paper discusses long-term change in snowfall, rainfall and mixed precipitation viewed in conjunction with air temperature and North Atlantic Oscillation (NAO) in winter (December–February). In the study of contemporary climate change and its effect on the hydrological cycle it is useful to focus on winter precipitation forms. A 146-year secular observation series from Kraków, spanning the period 1863–2008, was used to extract data on the number of days with precipitation and on precipitation amount broken down by form. Statistically significant trends were found in total and mixed precipitation, but not in snowfall and rainfall. The climate warming effect has contributed to a material decrease in the snowfall to total winter precipitation ratio during the second half of the 20th c. The highest impact of air temperature was found in the wintertime variation in number of days with snowfall while the NAO had a significant influence on the frequency and amount of both rainfall and snowfall.  相似文献   

19.
l. IntroductionPrevious studies have shown climatological and seasonal surface temperature and humld-ity dlstributlons over China (Wang and Gaffen, 200l ) and evaluated trends in seasonal meansof several surface humidity variables, rainfall, temperatures, and apparent temPerature for thelast half century (Easterling et al., 2000, Zhai et al., 1999, Zhai and Eskridge, l997, Zhai andRen, l997, Wang and Gaffen, 200l). However, trends in local temperatures, and particularlytrends in extreme he…  相似文献   

20.
It has been two and a half years since Fuqing ZHANG,a distinguished professor in the Department of Meteorology and Atmospheric Science at the Pennsylvania State University(PSU),passed away unexpectedly on 19 July 2019.This special issue is to commemorate Prof.Fuqing ZHANG,who has made tremendous contributions on predictability,data assimilation,and the dynamics of high impact weather.  相似文献   

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