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1.
The air–water exchange of momentum and scalars (temperature and water vapour) is investigated using the Lake-Atmosphere Turbulent EXchange (LATEX) dataset. The wind waves and swell are found to affect the coupling between the water surface and the air differently. The surface-stress vector aligns with the wind velocity in the presence of wind waves, but a wide range of stress–wind misalignment angles is observed during swell. The momentum transport efficiency decreases when significant stress–wind misalignment is present, suggesting a strong influence of surface wave properties on surface drag. Based on this improved understanding of the role of wave–wind misalignment, a new relative wind speed for surface-layer similarity formulations is proposed and tested using the data. The new expression yields a value of the von Kármán constant (\(\kappa \)) of 0.38, compared to 0.36 when using the absolute wind speed, as well as reduced data fitting errors. Finally, the ratios of aerodynamic to scalar roughness lengths are computed and various existing models in the literature are tested using least-square fitting to the observed ratios. The tests are able to discriminate between the performance of various models; however, they also indicate that more investigations are required to understand the physics of scalar exchanges over waves. 相似文献
2.
Fazel Nasim Berndtsson Ronny Uvo Cintia Bertacchi Madani Kaveh Kløve Bjørn 《Theoretical and Applied Climatology》2018,132(1-2):363-373
Theoretical and Applied Climatology - Lake Urmia in northwest Iran, once one of the largest hypersaline lakes in the world, has shrunk by almost 90% in area and 80% in volume during the last four... 相似文献
3.
In this paper,a relatively systematic climatological research on the onset of the Asian tropical summer monsoon(ATSM)was carried out.Based on a unified index of the ATSM onset,the advance of the whole ATSM was newly made and then the view that the ATSM firstly breaks out over the tropical eastern Indian Ocean and the middle and southern Indo-China Peninsula was further documented,which was in the 26th pentad(about May 10),then over the South China Sea(SCS)in the 28th pentad.It seems that the ATSM onset over the two regions belongs to the different stages of the same monsoon system.Then,the onset mechanism of ATSM was further investigated by the comprehensive analysis on the land-sea thermodynamic contrast,intraseasonal oscillation,and so on,and the several key factors which influence the ATSM onset were put forward.Based on these results,a possible climatological schematic map that the ATSM firstly breaks out over the tropical eastern Indian Ocean,the Indo-China Peninsula,and the SCS was also presented, namely seasonal evolution of the atmospheric circulation was the background of the monsoon onset;the enhancement and northward advance of the convections,the sensible heating and latent heating over the Indo-China Peninsula and its neighboring areas,the dramatic deepening of the India-Burma trough,and the westerly warm advection over the eastern Tibetan Plateau were the major driving forces of the summer monsoon onset,which made the meridional gradient of the temperature firstly reverse over this region and ascending motion develop.Then the tropical monsoon and precipitation rapidly developed and enhanced. The phase-lock of the 30-60-day and 10-20-day low frequency oscillations originated from different sources was another triggering factor for the summer monsoon onset.It was just the common effect of these factors that induced the ATSM earliest onset over this region. 相似文献
4.
Abstract Since 1969, meteorological and limnological measurements required for evaporation estimates by the energy budget method have been made almost continuously during the open water season at Perch Lake, a small (0.45 km2), shallow (mean depth 2 m) lake on the Canadian Shield. Hydrological measurements required for water budget calculations have been made continuously since 1970. Since ground water input to the lake has been found to be significant, energy budget estimates of evaporation are used in the water budget equation to estimate ground water inflow. Results are summarized as the long‐term averages along with the ranges of variation of the budget components observed during the eleven‐year period. 相似文献
5.
6.
The ordinary multidimensional reductive perturbation method is generalized so as to apply to the general case including the dissipative factor. With this the corresponding Cubic-Schrbdinger equation is deduced, and by the preliminary study of its solution, it shows that it is more admissible to consider atmospheric meso-scale systems as the nonlinear Cubic-Schrbdinger waves.With suitable boundary and initial conditions, the Cubic-Schrodinger equation is numerically integrated so as to investigate the possible dynamic mechanism as well as the impacts of the nonlinear action, turbulent friction and topogrphy to the formation of the LLJ. The results indicate that the downward transfer of the momentum and the effect of the surface friction are responsible for the concentration of the momentum in the layer between 850 and 700 hPa. The location of the horizontal concentration of momentum depends on the propagation of momentum, in the process the inertia-gravity internal wave is very important, whereas turbule 相似文献
7.
In order to study the characteristics of cold frontal motion over the arbitrary topography, the velocity of cold frontal movement is derived by using the one layer shallow-water model. The results show that there exist the retardation in upwind side and rapid descent in the lee slope when the cold front crosses the topography. 相似文献
8.
The possibility to use the observations of the total ozone values in the atmosphere (TO) in the end of polar winters as the
indicator of the cold accumulation in the troposphere and the type of its circulation is considered. The influence of TO over
polar regions on the approach of early and late circulation reconstructions in the stratosphere and the following weather
type in spring-summer season is concluded. 相似文献
9.
N. V. Shirshov R. M. Vil’fand P. P. Vasil’ev E. L. Vasil’eva 《Russian Meteorology and Hydrology》2014,39(6):416-419
The statistical model of the forecast (complex postprocessing) of surface air temperature with the lead time up to eight days is constructed using the results of the integration of hydrodynamic atmospheric models. The model is adapted to the area of the “Baikonur” using the method of central typing that allows increasing the accuracy of operational forecasts. The analysis of climate characteristics needed for constructing the proper statistical model for this area is given using both observational data for recent 25 years and the data of WMO (from the All-Russian Research Institute of Hydro-meteorological Information-World Data Center). Computed are the estimates of the accuracy of operational forecasts. 相似文献
10.
Characteristics of the Onset of the Asian Summer Monsoon and the Importance of Asian-Australian “Land Bridge” 总被引：12，自引：2，他引：12
Based on summarizing previous achievements and using data as long and new as possible, the onset characteristics of Asian summer monsoon and the role of Asian-Australian “land bridge” in the onset of summer monsoon are further discussed. In particular, the earliest onset area of Asian summer monsoon is comparatively analyzed, and the sudden and progressive characteristics of the onset of summer monsoon in different regions are discussed. Furthermore, the relationships among such critical events during the onset of Asian summer monsoon as the splitting of subtropical high belt over the Bay of Bengal (BOB), the initiation of convection over Indo-China Peninsula, the westward advance, reestablishment of South Asian High, and the rapid northward progression of convection originated from Sumatra in early summer are studied. The important impact of the proper collocation of the latent heating over Indo-China Peninsula and the sensible heating over Indian Peninsula on the splitting of the subtropical high belt, the deepening of BOB trough, the activating of Sri Lanka vortex (twin vortexes in the Northern and Southern Hemispheres), and the subsequent onset of South China Sea summer monsoon are emphasized. 相似文献
11.
Predictability of the Atmosphere 总被引：2，自引：0，他引：2
This paper makes a review on the predictability of the atmosphere. The essential problems of predictability theory, i.e., how a deterministic system changes to an undeterministic system (chaos) and how is the opposite (order within chaos), are discussed. Some applications of predictability theory are given. 相似文献
12.
Effect of the Interaction of Different Scale Vortices on the Structure and Motion of Typhoons 总被引：13，自引：1，他引：13
ＥｆｆｅｃｔｏｆｔｈｅＩｎｔｅｒａｃｔｉｏｎｏｆＤｉｆｆｅｒｅｎｔＳｃａｌｅＶｏｒｔｉｃｅｓｏｎｔｈｅＳｔｒｕｃｔｕｒｅａｎｄＭｏｔｉｏｎｏｆＴｙｐｈｏｏｎｓＣｈｅｎＬｉａｎｓｈｏｕ（陈联寿）（ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＭｅｔ６ｏｒｏｌｏｇｉｃ... 相似文献
13.
A new method of analysis namely, Singular Spectrum Analysis (SSA) is applied to the Indian Summer Monsoon (June-September) Rainfall (ISMR) series. The method is efficient in extracting the statistically significant oscillations with periods 2.8 and 2.3 year from the white noise of the ISMR series. The study shows that 2.8 / 2.3 year cycle captures the variability of the ISMR related to Southern Oscillation / Quasi Biennial Oscillation. The temporal structure of these oscillations show that these are in phase in extreme (excess and drought) monsoon conditions as well as in El Nino Southern Oscillation (ENSO) years. Both these oscillations show minimum variability during the period 1920-1940 and there is an increasing trend in the variability of these oscillations in the recent decades. The study enables to obtain pure signal consisting of reconstructed time series using these two Oscillations, from the original white noise series. 相似文献
14.
Dynamics of the surface air temperature and amount of precipitation in the Polar, Northern, and Southern Urals in the 20th
century is analyzed. Charts of the temperature distribution in the Urals for the period from 1961 to 2000, taking into account
the relief, are plotted in the geographical informational system on the basis of data of instrumental measurements at meteorological
stations with the use of the multiple regression analysis and raster modeling. The northeastern direction of the warming gradient
and increase of falling precipitations in the period under review is established. Time series of anomalies of the average
annual air temperature and amount of precipitation in the 20th century at three meteorological stations, situated in the Polar,
Northern, and Southern Urals, are analyzed. The tendency of the growth of anomalies of the average annual temperature and
total amount of precipitation is revealed. 相似文献
15.
H.G. Leighton 《大气与海洋》2013,51(1):43-52
Abstract A model to compute rapidly the absorption of solar radiation in the atmosphere is described. The model is based partially on the parameterization of Lacis and Hansen and also makes use of the delta‐Eddington method. In addition to absorption by ozone and water vapour, and scattering by air molecules and clouds, the mode1 includes absorption and scattering by aerosols. Good agreement is found in comparison with the Lacis and Hansen parameterization in the absence of clouds and aerosol. The present model represents an improvement in the treatment of scattering by clouds. Its main advantage though, is in its flexibility in allowing for interactions with the atmospheric aerosol. 相似文献
16.
ＮｕｍｅｒｉｃａｌＭｏｄｅｌｌｉｎｇｏｆｔｈｅＥｆｆｅｃｔｓｏｆＯｚｏｎｅｏｎｔｈｅＳｕｍｍｅｒＡｔｍｏｓｐｈｅｒｉｃＣｉｒｃｕｌａｔｉｏｎＷａｎｇＱｉａｎｑｉａｎ（王谦谦）；ＷａｎｇＹｉｎｈｕｉ（汪迎辉）；ＳｏｎｇＹｕ（宋煜）（Ｎａｍｉｎｇｉｎｓｔ... 相似文献
17.
《中国气象科学研究院年报》1994,(1)
ＡＮＩＮＦＥＲＥＮＣＥＯＦＴＨＥＴＥＭＰＥＲＡＴＵＲＥＩＮＴＨＥ１３ＴＨＣＥＮＴＵＲＹＯＦＣＨＩＮＡＺｈａｎｇＤｅ’ｅ（张德二）ＣｅｎｔｅｒｆｏｒＣｌｉｍａｔｉｃＲｅｓｅａｒｃｈＥＸＴＥＮＤＥＤＡＢＳＴＲＡＣＴＳｉｎｃｅｔｈｅｔｈｅｒｍａｌｏｐｔｉｍ... 相似文献
18.
YAN Bangliang 《大气科学进展》2005,22(5):741-750
The mechanism of the locking of the E1 Nino event onset phase to boreal spring （from April to June） in an intermediate coupled ocean-atmosphere model is investigated. The results show that the seasonal variation of the zonal wind anomaly over the equatorial Pacific associated with the seasonal variation of the ITCZ is the mechanism of the locking in the model. From January to March of the E1 Nino year, the western wind anomaly over the western equatorial Pacific can excite the downwelling Kelvin wave that propagates eastward to the eastern and middle Pacific by April to June. From April to December of the year before the E1 Nifio year, the eastern wind anomaly over the equatorial Pacific forces the downwelling Rossby waves that modulate the ENSO cycle. The modulation and the reflection at the western boundary modulate the time of the transition from the cool to the warm phase to September of the year before the E1 Nifio year and cause the strongest downwelling Kelvin wave from the reflected Rossby waves at the western boundary to arrive in the middle and eastern equatorial Pacific by April to June of the E1 Nino year. The superposition of these two kinds of downwelling Kelvin waves causes the El Nino event to tend to occur from April to June. 相似文献
19.
Time variations in the number of days with heavy precipitation based on data of 93 stations on the territory of Russia are
analyzed. Time series of precipitation, corrected by the elimination of main systematic errors of their measurement at the
level of their diurnal sums, are used, when computing. The diurnal precipitation sum, exceeding the average long-term diurnal
precipitation maximum by three times, was taken as the threshold quantitative criterion, defining “the day with heavy precipitation”
concept. This value varies within 10–15 mm/day on the territory of Russia. Extremums fluctuate from 5 to 40 mm/day. Absolute
values of linear trends of the annual number of days with heavy precipitation are comparatively small, they fluctuate within
±4 days on the whole territory of Russia. In relative terms, these variations are rather significant, reaching ±40% and more
of the corresponding average value for 65 years. The comparison of the spatial distribution of characteristics of linear trends
of the annual number of days with heavy precipitation and annual precipitation sum indicates their close conformity. 相似文献
20.
Numerical Experiments of the Effects of Initial Desert Moisture on the Climate Change 总被引：2，自引：0，他引：2
A numerical model with the p-sigma incorporated coordinate system and primitive equations is used to simulate the effect of initial soil moisture in desert areas on the climate change. The results show that the present deserts have a tendency to expand. When the initial soil moisture in the desert regions increases,the desert areas will shrink but can not disappear. The small deserts may not remain any longer when there are sources of water vapour around. Both the land-sea contrast and the topography are the background conditions of the present desert distribution through the mechanism of the downdrafts and the rare precipitation over the desert regions. The increase of the initial desert soil moisture will weaken the summer monsoon circulation and, consequently, the monsoonal precipitation. 相似文献