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1.
《气象研究与应用》1981,(6)
Wind observations differ fromthose of temperature and pressurein that two quantities must beobserved:direction and speedClose to the ground,wind speedincreases quickly with height.Both direction and speed are se-nsitive to the influence of buildi-ngs,trees,and other obstacles.It is therefore difficult to obtaina wind measurement representingair flow over a distance of sev-eral miles from the observingpoint. 相似文献
2.
ＡＭｏｄｅｌＳｔｕｄｙｏｆＴｈｒｅｅ－ＤｉｍｅｎｓｉｏｎａｌＷｉｎｄＦｉｅｌｄＡｎａｌｙｓｉｓｆｒｏｍＤｕａｌ－ＤｏｐｐｌｅｒＲａｄａｒＤａｔａＫｏｎｇＦａｎｙｏｕ（孔凡铀）；ＭａｏＪｉｅｔａｉ（毛节泰）（ＤｅｐａｒｔｍｅｎｔｏｆＧｅｏｐｈｙｓｉｃｓ... 相似文献
3.
A Statistical Analysis on the Effect of Vertical Wind Shear on Tropical Cyclone Development 总被引：6，自引：1，他引：6 
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下载免费PDF全文 Using tropical cyclone (TC) best track and intensity of the western North Pacific data from the Joint Typhoon Warning Center (JTWC) of the United States and the NCEP/NCAR reanalysis data for the period of 1992-2002, the effects of vertical wind shear on TC intensity are examined. The samples were limited to the westward or northwestward moving TCs between 5°N and 20°N in order to minimize thermodynamic effects. It is found that the effect of vertical wind shear between 200 and 500 hPa on TC intensity change is larger than that of the shear between 500 and 850 hPa, while similar to that of the shear between 200 and 850 hPa. Vertical wind shear may have a threshold value, which tends to decrease as TC intensifies. As the intensifying rate of TC weakens, the average shear increases. The large shear has the obvious trend of inhibiting TC development. The average shear of TC which can develop into typhoon (tropical depression or tropical storm) is below 7 m s-1 (above 8 m s-1). 相似文献
4.
During summer Monex-79, a variety of observing systems viz. research ships, research aircrafts, constant pressure balloons and geostationary satellite etc. were deployed, besides the regular conventional observations. The purpose of these additional systems was to make the best possible data for the studies on various aspects of monsoon circulation. The present study is aimed at the construction of vertical wind profile using cloud motion vectors obtained from GOES (I-O) satellite and to examine whether the constructed wind profiles improves the representation of the monsoon system, flow pattern etc. in the objective analysis. For this purpose, climatological normals of the wind field are considered as the initial guess and the objective analyses of the wind field are made with, first using only data from conventional observations over land areas, subsequently including the constructed winds from cloud motion vectors. These analyses are then compared with the standard analyses of wind field obtained fro 相似文献
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6.
Four comparative experiments and some supplementary experiments were conducted to examine the role of meridional wind stress anomalies and heat flux variability in ENSO simulations by using a high-resolution Ocean General Circulation Model （OGCM）. The results indicate that changes in the direction and magnitude of meridional wind stress anomalies have little influence on ENSO simulations until meridional wind stress anomalies are unrealistically enlarged by a factor of 5.0. However, evidence of an impact on ENSO simulations due to heat flux variability was found. The simulated Nino-3 index without the effect of heat flux anomalies tended to be around 1.0° lower than the observed, as well as the control run, during the peak months of ENSO events. 相似文献
7.
Hubert Gall��e Alexandre Trouvilliez C��cile Agosta Christophe Genthon Vincent Favier Florence Naaim-Bouvet 《Boundary-Layer Meteorology》2013,146(1):133-147
For the first time a simulation of blowing snow events was validated in detail using one-month long observations (January 2010) made in Adélie Land, Antarctica. A regional climate model featuring a coupled atmosphere/blowing snow/snowpack model is forced laterally by meteorological re-analyses. The vertical grid spacing was 2 m from 2 to 20 m above the surface and the horizontal grid spacing was 5?km. The simulation was validated by comparing the occurrence of blowing snow events and other meteorological parameters at two automatic weather stations. The Nash test allowed us to compute efficiencies of the simulation. The regional climate model simulated the observed wind speed with a positive efficiency (0.69). Wind speeds higher than 12 m s ?1 were underestimated. Positive efficiency of the simulated wind speed was a prerequisite for validating the blowing snow model. Temperatures were simulated with a slightly negative efficiency (?0.16) due to overestimation of the amplitude of the diurnal cycle during one week, probably because the cloud cover was underestimated at that location during the period concerned. Snowfall events were correctly simulated by our model, as confirmed by field reports. Because observations suggested that our instrument (an acoustic sounder) tends to overestimate the blowing snow flux, data were not sufficiently accurate to allow the complete validation of snow drift values. However, the simulation of blowing snow occurrence was in good agreement with the observations made during the first 20 days of January 2010, despite the fact that the blowing snow flux may be underestimated by the regional climate model during pure blowing snow events. We found that blowing snow occurs in Adélie Land only when the 30-min wind speed value at 2 m a.g.l. is >10 m s ?1. The validation for the last 10 days of January 2010 was less satisfactory because of complications introduced by surface melting and refreezing. 相似文献
8.
The investigations on the dynamies of the PBL have been developed in recent years. Some authors emphasized macro-dynamics and others emphasized micro-structure of the PBL. In this paper, we study and review some main characteristics of the wind field in the PBL from the view point connecting the macro-dynamics and micro-stucture of the PBL, thus providing the physical basis for the further research of the dynamics and the parameterization of the PBL. 相似文献
9.
《中国气象科学研究院年报》1994,(1)
ＴＨＥＥＦＦＥＣＴＯＦＴＨＥＳＬＩＧＨＴＬＹＩＮＣＬＩＮＥＤＴＥＲＲＡＩＮＯＮＴＨＥＷＩＮＤＳＨＥＡＲＮＥＡＲＴＨＥＳＵＲＦＡＣＥＺｈａｎｇＹｏｎｇｐｉｎｇ（张永萍），ＬｉＸｉｎｇｓｈｅｎｇ（李兴生），ＺｈｏｕＸｉｕｊｉ（周秀骥）ａｎｄＢｉａｎＬｉｎ... 相似文献
10.
Abstract Inertial oscillations in current records collected from May to September, 1977, at ten mooring sites 20–300 km apart in the semi‐enclosed sea off northwest British Columbia are analysed. Near‐surface oscillations were wind‐driven, clockwise rotary and circularly polarized; near‐bottom oscillations at depths of 155–330 m were clockwise rotary, less than 10% of near‐surface amplitudes, highly elliptical and poorly correlated with surface winds. In the open southwest sector of the region, near‐surface spectra possessed well‐defined peaks centred roughly 3.5% above the local inertial frequency (f), whereas spectra for the semi‐enclosed northern sector had broad peaks centred at f. The peak spectral frequency at the southeast corner of the mooring array was 6.5% below f and is linked to a Doppler shift by mean flow advection of comparatively high wavenumber inertial oscillations. A particularly vigorous wind‐generated surface “event” in mid‐June was coherent to 99% confidence over a distance of 300 km and persisted for more than 8 days at most locations and 11 days at a mooring at the edge of the continental shelf. (Typical durations for single wave groups were ～2 1/2 days.) This event, together with a similar less energetic event in August, was due to quasi‐resonant forcing by frontal winds associated with sequences of regularly spaced, eastward travelling extratropical cyclones. Estimated inertial wavelengths ranged from 300–700 km over the main portion of the sea to 85–95 km in the southeast corner. 相似文献
11.
Observed trends in severe weather conditions based on public alert statements issued by Environment Canada are examined for Canada. Changes in extreme heat and extreme cold events represented by various humidex and wind chill indices are analyzed for 1953–2012 at 126 climatological stations. Changes in heavy rainfall events based on rainfall amounts provided by tipping bucket rainfall gauges are analyzed for 1960–2012 at 285 stations. The results show that extreme heat events, defined as days with at least one hourly humidex value above 30, have increased significantly at more than 36% of the stations, most of which are located south of 55°N; days with nighttime hourly humidex values remaining above 20 have increased significantly at more than 52% of the stations, most of which are located south of 50°N. Extreme cold events represented by days with at least one hourly wind chill value below ?30 have decreased significantly at more than 76% of the stations across the country. No consistent changes were found in heavy rainfall events. Because city residents are very vulnerable to severe weather events, detailed results on changes in extreme heat, extreme cold, and heavy rainfall events are also provided for ten urban centres. 相似文献
12.
We present an analysis of data from a nearly 1-year measurement campaign performed at Høvsøre, Denmark, a coastal farmland area where the terrain is flat. Within the easterly sector upstream of the site, the terrain is nearly homogenous. This topography and conditions provide a good basis for the analysis of vertical wind-speed profiles under a wide range of atmospheric stability, turbulence, and forcing conditions. One of the objectives of the campaign was to serve as a benchmark for flow over flat terrain models. The observations consist of combined wind lidar and sonic anemometer measurements at a meteorological mast. The sonic measurements cover the first 100 m and the wind lidar measures above 100 m every 50 m in the vertical. Results of the analysis of observations of the horizontal wind-speed components in the range 10–1200 m and surface turbulence fluxes are illustrated in detail, combined with forcing conditions derived from mesoscale model simulations. Ten different cases are presented. The observed wind profiles approach well the simulated gradient and geostrophic winds close to the simulated boundary-layer height during both barotropic and baroclinic conditions, respectively, except for a low-level jet case, as expected. The simulated winds are also presented for completeness and show good agreement with the measurements, generally underpredicting the turning of the wind in both barotropic and baroclinic cases. 相似文献
13.
Ben B. Balsley Dale A. Lawrence Ronald F. Woodman David C. Fritts 《Boundary-Layer Meteorology》2013,147(1):165-178
We report results of preliminary high-resolution in situ atmospheric measurements through the boundary layer and lower atmosphere over the southern coast of Perú. This region of the coast is of particular interest because it lies adjacent to the northern coastal edge of the sub-tropical south-eastern Pacific, a very large area of ocean having a persistent stratus deck located just below the marine boundary layer (MBL) inversion. Typically, the boundary layer in this region during winter is topped by a quasi-permanent, well-defined, and very large temperature gradient. The data presented herein examine fine-scale details of the coastal atmosphere at a point where the edge of this MBL extends over the coastline as a result of persistent onshore flow. Atmospheric data were gathered using a recently-developed in-house constructed, GPS-controlled, micro-autonomous-vehicle aircraft (the DataHawk). Measured quantities include high-resolution profiles of temperature, wind, and turbulence structure from the surface to 1,300 m. 相似文献
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A variational method is developed to retrieve winds in the first step and then thermodynamic fields in the second step from Doppler radar observations. In the first step, wind fields are retrieved at two time levels: the beginning and ending times of the data assimilation period, simultaneously from two successive volume scans by 相似文献
16.
《中国气象科学研究院年报》1994,(1)
ＥＳＴＩＭＡＴＩＯＮＯＦＶＥＲＴＩＣＡＬＷＩＮＤＦＩＥＬＤＦＲＯＭＳＩＮＧＬＥ－ＤＯＰＰＬＥＲＲＡＤＡＲＲＨＩＯＢＳＥＲＶＡＴＩＯＮＳＰｅｎｇＨｏｎｇ（彭红）ａｎｄＧｅＲｕｎｓｈｅｎｇ（葛润生）ＩｎｓｔｉｔｕｔｅｏｆＭｅｓｏｓｃａｌｅＭｅｔｅｏｒｏｌ... 相似文献
17.
Wind speed variations are influenced by both natural climate and human activities. It is important to understand the spatial and temporal distributions of wind speed and to analyze the cause of its changes. In this study, data from 26 meteorological stations in the Jing–Jin–Ji region of North China from 1961 to 2017 are analyzed by using the Mann–Kendall(MK) test. Over the study period, wind speed first decreased by-0.028 m s-1 yr-1(p 0.01) in1961–1991, and then increased by 0.002 m s1-yr1-(p 0.05) in 1992–2017. Wind speed was the highest in spring(2.98 m s-1), followed by winter, summer, and autumn. The largest wind speed changes for 1961–1991 and1992–2017 occurred in winter(-0.0392 and 0.0065 m s-1 yr1-, respectively); these values represented 36% and 58%of the annual wind speed changes. More than 90.4% of the wind speed was concentrated in the range of 1–5 m s-1,according to the variation in the number of days with wind speed of different grades. Specifically, the decrease in wind speed in 1961–1991 was due to the decrease in days with wind speed of 3–5 m s-1, while the increase in wind speed in 1992–2017 was mainly due to the increase in days with wind speed of 2–4 m s-1. In terms of driving factors,variations in wind speed were closely correlated with temperature and atmospheric pressure, whereas elevation and underlying surface also influenced these changes. 相似文献
18.
《中国气象科学研究院年报》1994,(1)
ＡＮＡＬＹＳＩＳＯＦＭＥＡＮＷＩＮＤＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＩＮＴＨＥＡＴＭＯＳＰＨＥＲＩＣＳＵＲＦＡＣＥＬＡＹＥＲＯＦＴＨＥＧＲＡＳＳＬＡＮＤＡＲＥＡＩＮＮＯＲＴＨＣＨＩＮＡＸｕｅＨｅｎｇ（薛桁），ＺｈｕＲｕｉｚｈａｏ（朱瑞兆）ａｎｄＷｕＨｏ... 相似文献
19.
ＭｕｌｔｉｖａｒｉａｔｅＯｂｊｅｃｔｉｖｅＡｎａｌｙｓｉｓｏｆＷｉｎｄａｎｄＨｅｉｇｈｔＦｉｅｌｄｓｉｎｔｈｅＴｒｏｐｉｃｓＳ．Ｋ．Ｓｉｎｈａ，Ｓ．Ｇ．ＮａｒｋｈｅｄｋａｒａｎｄＳ．Ｒａｊａｍａｎｉ（ＩｎｄｉａｎｉｎｓｔｉｔｕｔｅｏｆＴｒｏｐｉｃａｌ... 相似文献
20.
E. Ekhart 《Theoretical and Applied Climatology》1951,3(1):91-109
Zusammenfassung Im ersten Abschnitt werden die wichtigsten Kennzeichen des Windklimas von Wien auf Grund der 50jährigen Stundenauswertungen des Anemographen an der Zentralanstalt für Meteorologie und Geodynamik, Hohe Warte, abgeleitet, wobei auch der Vektornatur des Windes entsprechend Rechnung getragen wird. Der zweite Abschnitt handelt von den lagjährigen Schwankungen im Windklima und deren Zusammenhang mit Änderungen anderer Klimaelemente (Temperatur und Niederschlag).
Mit 10 Textabbildungen. 相似文献
Summary Principal characteristics of the wind climate of Vienna are derived on the basis of hourly evaluations of anemographic records of 50 years at the Zentralanstalt für Meteorologie und Geodynamik, Hohe Warte, with due consideration of the vector nature of wind. In a second part the longterm variations of wind climate and their relation to variations of other climatic elements (temperature and precipitation) are dealt with.
Résumé Dans la première partie on établit les principau caractères du climat venteux de Vienne sur la base des valeurs horaires moyennes de 50 ans fournies par l'anémographe placé à la Zentralanstalt für Meteorologie und Geodynamik, Hohe Warte, en tenant compte de la nature vectorielle du vent. La deuxième partie traite des variations séculaires du climat venteux et de leurs relations avec les variations d'autres éléments climatiques tels que la température et la pluie.
Mit 10 Textabbildungen. 相似文献