Roanu台风中突然天气变化的自动气象站资料评估

以斯里兰卡南部5.936 108°N、80.574 900°E处的自动气象站（AWS）的气象时间序列观测数据为依据,对2015年12月至2016年10月大气边界层的变化进行了定量分析.结果表明,印度洋北部的季风、气温、气压、相对湿度、降水和向下短波辐射的扰动随着季风的逆转而变化.2016年5月台风Roanu经过时,气压降低、相对湿度增大、降水增强和向下短波辐射减小,其特征是温度、相对湿度、降水和风速均迅速增加,之后气温和降水下降,而气压、向下短波辐射在急剧减小之后又急剧增大.自动气象站记录了台风到达前的气象条件,并自2016年5月13日起各个参数开始响应台风变化.从2016年5月28日开始,自动气象站记录台风通过后的气象条件,此时降水和向下辐射均减少.这些信号说明应用自动气象站可以持续观测台风条件.这项研究表明,斯里兰卡南部地区的气象数据可以用来进行天气评估,并可以对南部沿海地区的海气关系现象进行分析.此外,自动气象站的现场数据可以用作模型验证和参数化.     

西南季风爆发前后大理近地层风场及湍流通量的变化特征

利用2008年4~5月大理国家气候观象台近地面层观测系统的梯度、涡动相关通量观测资料,结合背景场环流分析,分析了西南季风爆发前后大理近地面层的风速、风向变化特征、风速廓线和垂直切变变化特征以及动量、感热和潜热通量变化特征。结果显示:西南季风爆发前,大理近地层风向以东南风为主,平均风速较大;风速日变化的双峰型特征较显著,风速的垂直切变大,动量通量数值较大且日变化特征较明显。西南季风爆发后,大理近地层西北风频率显著增加,平均风速减小;风速日变化以单锋型为主,风速垂直切变较前期显著减小,动量通量数值减小而日变化特征较不显著。西南季风开始前后大理地气热量交换都以潜热为主,西南季风开始前一旬期间,潜热通量的逐日变化特点是随时间逐渐减少,感热通量逐渐增大,二者差值逐渐减小;西南季风开始后潜热通量的逐日变化为逐渐增大而感热通量逐渐减少,二者差值逐渐增大。就月平均值的日变化而言,潜热通量峰值变化不大,雨季略低于干季的4月;感热通量4~6月的月平均逐月降低。其原因既与雨季天气的变化有关,也与下垫面状况的改变相联系。     

Conditions leading to the onset of the Indian monsoon: A satellite perspective

Summary The summer monsoon onset-2004 over the Kerala Coast (Southern tip of the Indian Peninsula) was monitored in real-time using the Tropical Rainfall Measuring Mission (TRMM)/TMI derived total precipitable water vapor, wind speed and sea surface temperature (SST), National Centre for Environmental Prediction (NCEP) and QuikScat wind data. The 2004 onset was of a gradual type, with an early start (24 May), followed by slow growth to full strength (10 June). Hence, the unambiguous forecasting of such onsets becomes very difficult. The water vapor build up over the western Arabian Sea is one of the necessary conditions that gives us a lead time of two and half weeks for the onset of monsoon. The strength of the Hadley cell (monitored using NCEP meridional wind), which is associated with a large convective heat source is also used as a predictive parameter with a lead-time of two weeks. The other dynamical conditions considered are the early May propagation of the Madden Julian Oscillation (MJO) followed by a second MJO, which began in the Western Indian Ocean (WIO) and the kinetic energy over the South East Arabian Sea, with an early start around 24 May (50 m²/s²) and strengthening around 10 June (80 m²/s²). The setting of large-scale monsoon current using various satellite derived parameters and the distinct features for the year 2004 have been delineated.     

Stratospheric zonal wind and temperature in relation to summer monsoon rainfall over India

Summary  The interannual variability of the Indian summer monsoon (June–September) rainfall is examined in relation to the stratospheric zonal wind and temperature fluctuations at three stations, widely spaced apart. The data analyzed are for Balboa, Ascension and Singapore, equatorial stations using recent period (1964–1994) data, at each of the 10, 30 and 50 hPa levels. The 10 hPa zonal wind for Balboa and Ascension during January and the 30 hPa zonal wind for Balboa during April are found to be positively correlated with the subsequent Indian summer monsoon rainfall, whereas the temperature at 10 hPa for Ascension during May is negatively correlated with Indian summer monsoon rainfall. The relationship with stratospheric temperatures appears to be the best, and is found to be stable over the period of analysis. Stratospheric temperature is also significantly correlated with the summer monsoon rainfall over a large and coherent region, in the north-west of India. Thus, the 10 hPa temperature for Ascension in May appears to be useful for forecasting summer monsoon rainfall for not only the whole of India, but also for a smaller region lying to the north-west of India. Received July 30, 1999 Revised March 17, 2000     

A Study of Orographic Blocking and Barrier Wind Development Upstream of the Southern Alps, New Zealand

Summary Upper level and surface wind data for 1994 are used to provide an initial identification of the orographic effect on regional airflow patterns upwind of the mountain barrier. A case study of the development of upstream blocking and barrier jets is also provided. The predominance of gradient airflow from between northwest and southwest through this region results in frequent trans-mountain winds. The mountains are seen to have a major effect on airflow in the lowest 2000 m above sea level, with clear evidence of orographic blocking and barrier wind development. Some variability in the extent of this blocking was noted during 1994, which appeared to be associated with changes in the synoptic circulation and air mass characteristics. The frequent occurrence of southwesterly winds between 300 m and 2000 m indicates significant deflection of the predominant winds to follow the southwest-northeast orientation of the mountains. These southwesterly barrier winds occur in opposition to the apparent pressure gradient. Northeasterly barrier winds occur mainly below 300 m, and represent a down-gradient, localised flow that is frequently separated from overlying northwesterly gradient winds by a transitional layer, within which the wind backs with height. The controls of the extent of orographic blocking are only assessed superficially, due to the lack of good thermodynamic data upstream of the mountains, although a combination of wind speed and atmospheric stability is obviously important. These initial results provide a useful insight into the extent of orographic effects on regional windfields, which will serve as the basis for future observational and modelling studies. Received June 11, 1998 Revised April 16, 1999     

The association of surface wind stresses over Indian Ocean with monsoon rainfall

Summary Variability of Indian summer monsoon rainfall is examined with respect to variability of surface wind stresses over Indian Ocean. The Indian Ocean region extending from 40°–120° E, and 30° S–25° N, has been divided into 8 homogeneous subregions, viz (1) Arabian Sea (AS), (2) Bay of Bengal (BB), (3) West-equatorial Indian Ocean (WEIO), (4) Central-equatorial Indian Ocean (CEIO), (5) East-equatorial Indian Ocean (EEIO), (6) South-west Indian Ocean (SWIO), (7) South-central Indian Ocean (SCIO), and (8) South-east Indian Ocean (SEIO). The period of study extends for 13 years from 1982–1994. Monthly NCEP surface wind stress data of five months – May through September, have been used in the study. The spatial variability of seasonal and monthly surface wind stresses shows very low values over CEIO and EEIO and very high values over AS, SWIO, and SEIO regions. On the seasonal scale, all India summer monsoon rainfall (AISMR) shows concurrent positive relationships with the surface wind stresses over AS, BB, WEIO, SWIO and SCIO and negative relationships with the surface wind stresses over EEIO and SEIO. The relationships of AISMR with the surface wind stresses over AS and WEIO are significant at 5% level. The concurrent relationships between monthly surface wind stresses over these 8 oceanic sub-regions and monthly subdivisional rainfalls over 29 sub-divisions have been studied. The rainfalls over the subdivisions in the central India and on the west coast of India are found to be significantly related with surface wind stresses over AS, SWIO, SCIO. Monthly subdivisional rainfalls of four subdivisions in the peninsular India show negative relationship with BB surface wind stresses. May surface wind stresses over AS, BB, WEIO, CEIO and SWIO have been found to be positively related with ensuing AISMR. The relationship with AS wind stresses is significant at 5% level and hence may be considered as a potential predictor of AISMR. Received May 21, 2001 Revised October 8, 2001     

Urban–rural contrasts of meteorological parameters in Łódź

Summary Data from two automatic stations in Łódź (one urban and one rural) for the period 1997–2002 are analyzed to reveal urban–rural contrasts of such parameters as air temperature, relative humidity, water vapour pressure and wind speed. Under favourable weather conditions the highest temperature differences between the urban and rural station exceeds 8 °C. Relative humidity is lower in the town, sometimes by more than 40%. Water vapour pressure differences can be either positive (up to 5 hPa) or negative (up to −4 hPa). Wind speed at the urban station is on average lower by about 34% in night and 39% during daytime. Regression analysis shows that for rural winds lower than 1.13 m s⁻¹ urban winds can be stronger than rural speeds. Attention has also been paid to singularities in the course of the analyzed parameters over 24 hour periods. It is shown that the typical course of the urban heat island intensity under favourable conditions is similar in all season. Four stages of this course have been distinguished. Wind speed differences also seem to change in a typical way. Case studies show that humidity contrasts, unlike temperature, can evolve in different ways under fine weather conditions. Types of relative humidity evolution are proposed.     

Seasonal Variations in the Vertical Structure of Water Vapor Optical Depth in the Lower Troposphere over a Tropical Station

Spatio-temporal variations of water vapor optical depth in the lower troposphere (450-3850 m) over Pune (18o32’N, 73o51’E, 559 m Above Mean Sea Level), India have been studied over a period of five years. The mean ver-tical structure showed that the moisture content is greatest at the lowest level and decreases with increasing altitude, except in the south-west monsoon season (June to September) when an increase upto 950 m has been found. Optical depths are maximum in the monsoon season. The increase from pre-monsoon (March-May) to monsoon season in moisture content on an average is by about 58% in the above altitude range. The temporal variations in surface Rela-tive Humidity and optical depth at 450 m show positive correlation. The amplitude of seasonal oscillation is the larg-est at 1465 m altitude. The time-height cross-sections of water vapor optical depths in the lower troposphere showed a contrast between years of good and bad monsoon.     

Evolution of geophysical parameters over the Indian Ocean region during contrasting monsoon years of 2002 and 2003 using TRMM/TMI data

Summary The evolution of geophysical parameters over Indian Ocean during two contrasting monsoon years 2002 (drought) and 2003 (normal) were studied using TRMM/TMI satellite data. Analysis indicates that there was a lack of total water vapour (TWV) build up over Western Indian Ocean (WIO) during May 2002 (drought) when compared to 2003 (normal). Negative (positive) TWV anomalies were found over the WIO in May 2002 (2003). In 2002, negative SST anomaly of ∼1.5 °C is found over entire WIO when compared to 2003. Anomalously high sea surface wind speed (SWS) anomaly over the South West Indian Ocean (SWIO) and WIO would have resulted in cooling of the sea surface in May 2002 in comparison to 2003. In 2003 the wind speed anomaly over entire WIO and Arabian Sea (AS) was negative, whereas sea surface temperature (SST) anomaly was positive over the same region, which would have resulted in higher moisture availability over these regions. A negative (positive) TWV anomaly over Eastern Arabian Sea (EAS) and positive (negative) anomaly over WIO forms a dipole structure. In the month of June no major difference is seen in all these parameters over the Indian Ocean. In July 2002 the entire WIO and AS was drier by 10–15 mm as compared to 2003. The pentad (5 day) average TWV values shows high (>55 mm) TWV convergence over EAS and Bay of Bengal (BoB) during active periods of 2003, which gives high rainfall over these regions. However, during 2002 although TWV over BoB was >55 mm but it was ∼45–55 mm over EAS during entire July and hence less rainfall. The evaporation has been calculated from the bulk aerodynamic formula using TRMM/TMI geophysical products. It has been seen that the major portion of evaporative moisture flux is coming from southern Indian Ocean (SIO) between 15 and 25° S. Evaporation in June was more over AS and SIO in 2003 when compared to 2002 which may lead to reduce moisture supply in July 2002 and hence less rainfall compared to July 2003.     

All India summer monsoon rainfall prediction using an artificial neural network

The prediction of Indian summer monsoon rainfall (ISMR) on a seasonal time scales has been attempted by various research groups using different techniques including artificial neural networks. The prediction of ISMR on monthly and seasonal time scales is not only scientifically challenging but is also important for planning and devising agricultural strategies. This article describes the artificial neural network (ANN) technique with error- back-propagation algorithm to provide prediction (hindcast) of ISMR on monthly and seasonal time scales. The ANN technique is applied to the five time series of June, July, August, September monthly means and seasonal mean (June + July + August + September) rainfall from 1871 to 1994 based on Parthasarathy data set. The previous five years values from all the five time-series were used to train the ANN to predict for the next year. The details of the models used are discussed. Various statistics are calculated to examine the performance of the models and it is found that the models could be used as a forecasting tool on seasonal and monthly time scales. It is observed by various researchers that with the passage of time the relationships between various predictors and Indian monsoon are changing, leading to changes in monsoon predictability. This issue is discussed and it is found that the monsoon system inherently has a decadal scale variation in predictability. Received: 13 March 1999 / Accepted: 31 August 1999     

Characteristics of Spatiotemporal Distribution of Sea Surface Wind along the East Coast of Guangdong Province

We analyzed the frequency distribution characteristics of wind speeds occurring at different offshore sites within a range of 0–200 km based on the sea surface wind data captured via buoys and oil platforms located along the east coast of Guangdong Province. The results of the analysis showed that average wind speed measured for each station reached a maximum in winter while minima occurred in summer, corresponding to obvious seasonal variation, and average wind speed increased with offshore distance. The prevailing wind direction at the nearshore site is the easterly wind, and the frequency of winds within 6–10 m s^–1 is considerable with that of winds at > 10 m s^–1. With the increase of the offshore distance, the winds were less affected by the land, and the prevailing wind direction gradually became northerly winds, predominately those at > 10 m s^–1. For areas of shorter offshore distance (< 100 km), surface wind speeds fundamentally conformed to a two-parameter Weibull distribution, but there was a significant difference between wind speed probability distributions and the Weibull distribution in areas more than 100 km offshore. The mean wind speeds and wind speed standard deviations increased with the offshore distance, indicating that with the increase of the wind speed, the pulsation of the winds increased obviously, resulting in an increase in the ratio of the mean wind speed to the standard deviation of wind speed. When the ratio was large, the skewness became negative. When a relatively great degree of dispersion was noted between the observed skewness and the skewness corresponding to the theoretical Weibull curve, the wind speed probability distribution could not be adequately described by a Weibull distribution. This study provides a basis for the verification of the adaptability of Weibull distribution in different sea areas.     

Generation and termination of Indian Ocean dipole events in 2003, 2006 and 2007

Evolution of Indian Ocean Dipole (IOD) events in 2003, 2006 and 2007 is investigated using observational and re-analysis data products. Efforts are made to understand various processes involved in three phases of IOD events; activation, maturation and termination. Three different triggers are found to activate the IOD events. In preceding months leading to the IOD evolution, the thermocline in southeastern Indian Ocean shoals by reflection of near equatorial upwelling Rossby waves at the East African coast into anomalous upwelling equatorial Kelvin waves. Strengthening (weakening) of northern (southern) portion of ITCZ in March/April and May/June of IOD years, leads to strengthening of alongshore winds along Sumatra/Java coasts. With the combined shallow thermocline and increased latent heat flux due to enhanced wind speeds, the SST in the southeastern Indian Ocean cools in following months. On intraseasonal time scales convection-suppressing phase of Madden-Julian oscillation (MJO) propagates from west to east in May/June of IOD year, and easterlies associated with this phase of MJO causes further shoaling of thermocline in southeastern Indian Ocean, through anomalous upwelling Kelvin wave. All these three mechanisms appear to be involved in initiating IOD event in 2006. On the other hand, except the strengthening/weakening of ITCZ, all other mechanisms are involved in activation of 2003 IOD event. Activation of 2007 IOD event was due to propagation of convection-suppressing MJO in May/June and strengthening of mean winds along Sumatra/Java coast from March to June through changes in convection. The IOD events matured into full-fledged events in the following months after activation, by surface heat fluxes, vertical and horizontal advection of cool waters supported by local along-shore upwelling favorable winds and remote equatorial easterly wind anomalies through excitation of upwelling Kelvin waves. Propagating MJO signals in the tropical Indian Ocean brings significant changes in evolution of IOD events on MJO time scales. Termination of 2003 and 2007 IOD events is achieved by strong convection-enhancing MJOs propagating from west to east in the tropical Indian Ocean which deepen the thermocline in the southeastern equatorial Indian Ocean. IOD event in 2006 was terminated by seasonal reversal of monsoon winds along Sumatra/Java coasts which stops the local coastal upwelling.     

Impact of air pollution on summer surface winds in Xi’an

By analysis of observation data, this paper demonstrates that pollution particles could reduce surface wind speed through blocking solar radiation to the ground. The comparation between temperature at the lowland meteorological station Xi’an and that over the nearby highland station Mt. Hua suggests that surface solar radiation at Xi’an is reduced due to the increasing anthropogenic aerosols. The reduced surface energy suppresses the atmospheric instability and convective flows, and thus the downward transfer of faster winds aloft is reduced. Consequently, wind speeds near surface are weakened. This reduction of surface winds is shown by the significant reverse trends of wind speeds over the two stations at different elevations. The aerosols’ effects on winds are also manifested in the trends of radionsonde wind speed. The decreased surface winds in Xi’an have also reduced local pan evaporation.     

South Asian summer monsoon precipitation variability: Coupled climate model simulations and projections under IPCC AR4

Summary South Asian summer monsoon precipitation and its variability are examined from the outputs of the coupled climate models assessed as part of the Intergovernmental Panel on Climate Change Fourth Assessment. Out of the 22 models examined, 19 are able to capture the maximum rainfall during the summer monsoon period (June through September) with varying amplitude. While two models are unable to reproduce the annual cycle well, one model is unable to simulate the summer monsoon season. The simulated inter-annual variability from the 19 models is examined with respect to the mean precipitation, coefficient of variation, long-term trends and the biennial tendency. The model simulated mean precipitation varies from 500 mm to 900 mm and coefficient of variation from 3 to 13%. While seven models exhibit long-term trends, eight are able to simulate the biennial nature of the monsoon rainfall. Six models, which generate the most realistic 20th century monsoon climate over south Asia, are selected to examine future projections under the doubling CO₂ scenario. Projections reveal a significant increase in mean monsoon precipitation of 8% and a possible extension of the monsoon period based on the multi-model ensemble technique. Extreme excess and deficient monsoons are projected to intensify. The projected increase in precipitation could be attributed to the projected intensification of the heat low over northwest India, the trough of low pressure over the Indo-Gangetic plains, and the land–ocean pressure gradient during the establishment phase of the monsoon. The intensification of these pressure systems could be attributed to the decline in winter/spring snowfall. Furthermore, a decrease of winter snowfall over western Eurasia is also projected along with an increase of winter snowfall over Siberia/eastern Eurasia. This projected dipole snow configuration during winter could imply changes in mid-latitude circulation conducive to subsequent summer monsoon precipitation activity. An increase in precipitable water of 12–16% is projected over major parts of India. A maximum increase of about 20–24% is found over the Arabian Peninsula, adjoining regions of Pakistan, northwest India and Nepal. Although the projected summer monsoon circulation appears to weaken, the projected anomalous flow over the Bay of Bengal (Arabian Sea) will support oceanic moisture convergence towards the southern parts of India and Sri Lanka (northwest India and adjoining regions). The ENSO-Monsoon relationship is also projected to weaken.     

广汉机场春季地面风的变化特征及其对飞行训练的影响

利用广汉机场2010~2014年遥测地面风场资料,分析了春季地面风的年变化、月变化以及日变化特征,讨论了地面风对飞行训练的影响。结果表明:广汉机场春季盛行偏北风,此外主要还受到北西北、北东北风的影响,飞行训练易遭遇左侧风;4~5m/s以及6m/s以上的地面风日数年变化不大,但春季最大风速的年变化差异较大;3~5月月平均地面风速呈递增特征,从3月到5月主导风向由北风顺时针变化为东北风,东东南、东南、南东南风频率逐渐增加,左侧风以及逆风影响增大。地面风速的日变化呈现出“一峰一谷”的大陆型变化特征,即白天风速大,夜间风速小,午后风速最大,4~5m/s的风受日变化影响大,6m/s以上的风主要受天气系统的影响。      

THE TEMPORAL AND SPATIAL DISTRIBUTION OF SEA SURFACE WIND ALONG THE COAST OF GUANGDONG PROVINCE IN CHINA

Temporal and spatial distribution characteristics of sea surface wind in Guangdong''s coastal areas were analyzed with data from four offshore observational stations between 2012 and 2015. The results are shown as follows: (1) The probability distribution of wind speed was basically consistent with Gaussian distribution characteristics; winds of Beaufort force 6 or higher were observed mainly in far offshore stations from October to March. (2) The probability distribution of wind direction was represented well by Weibull distribution. The deviation of wind direction of far station was relatively small for it was mainly controlled by monsoon over the South China Sea, while the near offshore station had a relatively large diurnal variation because of the influence of local synoptic systems such as sea-land breeze. (3) There were significant seasonal differences in wind speed and direction observed by different offshore observational stations. In strong wind seasons, the deviation of wind direction was relatively small while the deviation of wind speed was relatively large, and vice versa. In contrast with Class I station, the other three stations exhibited approximately normal distribution of wind direction and wind speed deviations. (4) Wind direction diurnal variation was moderate in windy periods, while it was obvious in relatively lower speed conditions. The deviation of wind speed in windy periods was generally greater because it was influenced by mesoscale weather systems for 10-20 h, and the influence was complicated, resulting in greater local differences in wind speed.     

Modification of the local winds due to hypothetical urbanization of the Zagreb surroundings

Summary The aim of this study was to investigate possible effects of two hypothetical scenarios of the urbanization of Zagreb’s surroundings on the local winds, which are established under summertime anticyclonic conditions. For this purpose, the nonhydrostatic mesoscale meteorological model MEMO was applied to the greater Zagreb area. Three simulations were performed. One employed the current land-use distribution, while the other two corresponded to an increase of the densely urbanized area by 12.5% (test 1) and 37.5% (test 2), respectively. Apart from the hypothetically urbanized areas, where average surface wind speed reductions of 8% and 18% were obtained for test 1 and test 2, respectively, the rest of the domain was not significantly affected by hypothetical urbanization. The differences between the wind vectors for the predicted current state and the hypothetical state were more pronounced and found at higher altitudes during the night compared to daytime values. For all three simulations the same diurnal variation of the depth of anabatic/katabatic wind flow generated on south-facing slopes of 1 km high mountain Medvednica was obtained. During the night the depth of well-developed katabatic flow was about 370 m, while during the day the depth of anabatic flow grew from about 550 m in the late morning up to about 1140 m in the late afternoon. Received October 27, 2000 Revised August 4, 2001     

The feasibility of estimating large-scale surface wind fields for the summer MONEX using cloud motion and ship data

Cloud motion data were compared to ship observations over the Indian Ocean during the summer monsoon, 1 May to 31 July 1979, with the objective of using the cloud data for estimating surface wind and ultimately the wind stress on the ocean. The cloud-ship comparison indicated that the cloud motions could be used to estimate surface winds within reasonable accuracy bounds, 2.6 m s^-1 r.m.s. speeds and 22° to 44° r.m.s. directions (22° r.m.s. for winds < 10 m s^-1). A body of statistics is presented which can be used to construct an empirical boundary layer with the eventual goal of producing a stress analysis for the summer MONEX from cloud motion data.     

Evidence of a Convective Boundary Layer Developingon the Antarctic Plateau during the Summer

Summary The development of a convective boundary layer over the Antarctic Plateau is documented by a Doppler minisodar data-set recorded during a 10 day campaign in January 1997. The vertical velocities associated with thermals do not exceed 1 m/s, while the depth of the convective layer, usually less than 200 m, never surpasses 300 m. Measurements of momentum flux, sensible heat flux, wind speed and radiation budget show characteristics that are typical of a convective boundary layer evolution. The diurnal behaviour of absolute humidity, however, exhibits features that are not expected, e.g. anticorrelation with incoming net radiation and air temperature. Received October 30, 1998 Revised May 26, 1999     

Water vapour flux profiles in the convective boundary layer

Summary Water vapour flux profiles in the atmospheric boundary layer have been derived from measurements of water vapour density fluctuations by a ground-based Differential Absorption Lidar (DIAL) and of vertical wind fluctuations by a ground-based Doppler lidar. The data were collected during the field experiment LITFASS-2003 in May/June 2003 in the area of Lindenberg, Germany. The eddy-correlation method was applied, and error estimates of ±50 W/m² for latent heat flux were found. Since the sampling error dominates the overall measurement accuracy, time intervals between 60 and 120 min were required for a reliable flux calculation, depending on wind speed. Rather large errors may occur with low wind speed because the diurnal cycle restricts the useful interval length. In the lower height range, these measurements are compared with DIAL/radar-RASS fluxes. The agreement is good when comparing covariance and error values. The lidar flux profiles are well complemented by tower measurements at 50 and 90 m above ground and by area-averaged near surface fluxes from a network of micrometeorological stations. Water vapour flux profiles in the convective boundary layer exhibit different structures mainly depending on the magnitude of the entrainment flux. In situations with dry air above the boundary layer a positive entrainment flux is observed which can even exceed the surface flux. Flux profiles which linearly increase from the surface to the top of the boundary layer are observed as well as profiles which decrease in the lower part and increase in the upper part of the boundary layer. In situations with humid air above the boundary layer the entrainment flux is about zero in the upper part of the boundary layer and the profiles in most cases show a linear decrease.