A seasonal grade division of the global offshore wind energy resource

Under the background of energy crisis, the development of renewable energy will significantly alleviate the energy and environmental crisis. On the basis of the European Centre for Medium-Range Weather Forecasts（ECMWF）interim reanalysis（ERA-interim） wind data, the annual and seasonal grade divisions of the global offshore wind energy are investigated. The results show that the annual mean offshore wind energy has great potential. The wind energy over the westerly oceans of the Northern and Southern Hemispheres is graded as Class 7（the highest）, whereas that over most of the mid-low latitude oceans are higher than Class 4. The wind energy over the Arctic Ocean（Class 4） is more optimistic than the traditional evaluations. Seasonally, the westerly oceans of the Northern Hemisphere with a Class 7 wind energy are found to be largest in January, followed by April and October, and smallest in July. The area of the Class 7 wind energy over the westerly oceans of the Southern Hemisphere are found to be largest in July and slightly smaller in the other months. In July, the wind energy over the Arabian Sea and the Bay of Bengal is graded as Class 7, which is obviously richer than that in other months. It is shown that in this data set in April and October, the majority of the northern Indian Ocean are regions of indigent wind energy resource.

VARYING SEASONS' MESOSCALE WIND FIELD CIRCULATION IN HAINAN ISLAND

Using a one-level numerical diagnostic model, the features of surface wind fields in Hainan Island and Leizhou Peninsula and maritime area around it are studied. In the experiments with prevailing synoptic situation for varying seasons there are obvious deflection flows, terrain slope drafts, convergence lines, sea/land breeze and mountain/valley breeze, and difference in season accounts for the features found in the mesoscale distribution.The complex terrain and seatland distribution in the area is shown to be the important cause for the formation of varying mesoscale circulation, and close relationships between local climatic distribution feature and mesoscale circulation are then revealed.

The seasonal variations in the significant wave height and sea surface wind speed of the China's seas

Long-term variations in a sea surface wind speed （WS） and a significant wave height （SWH） are associated with the global climate change, the prevention and mitigation of natural disasters, and an ocean resource exploitation, and other activities. The seasonal characteristics of the long-term trends in China＇s seas WS and SWH are determined based on 24 a （1988-2011） cross-calibrated, multi-platform （CCMP） wind data and 24 a hindcast wave data obtained with the WAVEWATCH-III （WW3） wave model forced by CCMP wind data. The results show the following. （1） For the past 24 a, the China＇s WS and SWH exhibit a significant increasing trend as a whole, of 3.38 cm/（s.a） in the WS, 1.3 cm/a in the SWH. （2） As a whole, the increasing trend of the China＇s seas WS and SWH is strongest in March-April-May （MAM） and December-January-February （DJF）, followed by June-July-August （JJA）, and smallest in September-October-November （SON）. （3） The areal extent of significant increases in the WS was largest in MAM, while the area decreased in JJA and DJF; the smallest area was apparent in SON. In contrast to the WS, almost all of China＇s seas exhibited a significant increase in SWH in MAM and DJF; the range was slightly smaller in JJA and SON. The WS and SWH in the Bohai Sea, the Yellow Sea, East China Sea, the Tsushima Strait, the Taiwan Strait, the northern South China Sea, the Beibu Gull and the Gulf of Thailand exhibited a significant increase in all seasons. （4） The variations in China＇s seas SWH and WS depended on the season. The areas with a strong increase usually appeared in DJF.

Seasonal Variations of Solar Wind Parameters during Solar Cycles 23 and 24

In this paper, we analyzed diurnal and annual seasonal variations of solar wind parameters such as interplanetary magnetic field (IMF), proton density (N), solar wind speed (V) and solar wind dynamic pressure (Pdym), during the solar cycles 23 and 24. Our study shows that strong geomagnetic disturbances are observed at the equinoxes during both solar cycles. The highest proton densities are observed at solstices during both solar cycles. The greatest solar wind speeds are observed at the equinoxes of solar cycle 23 and at the solstices of solar cycle 24. The highest solar wind dynamic pressures are observed at the solstices of both solar cycles. We also observed an asymmetrical evolution of the seasonal diurnal values of the solar wind parameters during the two cycles, except for the proton density. Our investigations also highlight the fact that the seasonal diurnal values of the solar wind parameters are significant at solar cycle 23 compared to solar cycle 24 characterized by a global weak in solar plasma conditions since the deep minimum that followed the solar cycle 23 leading to an absence of a persistent polar coronal hole. The drop observed in polar field and solar winds parameters during solar cycle 24 is reproduced on seasons (solstices and equinoxes). The solar cycle 23 and 24 appear to be two magnetically opposite solar cycles regardless the time scales.

基于水电储能调节的风光水发电联合优化调度策略

为缓解新能源装机容量扩大引起的弃风弃光现象,在已有梯级水电上下电站之间加入储能泵站,提出风光水储短期优化调度策略。构建以风光水储系统负荷跟踪误差最小、梯级水电站发电量最大和梯级水电站发电耗水量最小的多目标优化调度模型;提出基于季节性自回归移动平均(seasonal auto-regressive lntegrated moving average, SARIMA)模型和Copula函数的风光出力预测模型作为优化调度模型的边界条件,通过SARIMA预测模型将风光出力历史数据分解为季节性分量、趋势分量以及随机噪声余项进行全天96个调度时段风光出力预测,并叠加上基于Copula函数生成风光出力预测误差,然后通过拉丁超立方采样以及K-means聚类进行场景生成和缩减得到5个风光出力场景。选取风光典型日出力数据为例进行算例分析,算例结果表明:所提预测模型较SARIMA模型可以显著提高预测准确度,模型预测风光出力均方根误差从33.34、229.49 MW分别下降至0.697、9.534 MW;所提优化调度策略可以在全年丰、平、枯水期有效减少弃风弃光现象,并可将过剩新能源中的50%转化为上级水库储存水能。

高海拔深切峡谷典型季节风参数日变化特征

为确定高海拔深切峡谷典型季节风特性参数的日变化特征,依托青藏高原某横跨雅鲁藏布江的大跨度桥梁为工程背景,开展桥位风特性现场实测,选取冬季、夏季没有较强天气系统作用的典型时段,统计分析风速、风向、风攻角、风速剖面等平均风参数,采用db8小波提取时变平均风速,通过非平稳风速模型分析紊流强度、积分尺度、紊流功率谱等脉动风参数。研究结果表明:峡谷风场风速、风向均呈现以天为周期的规律波动,风速在凌晨和上午相对较小,不同季节风速起落时间不一致,夏季、冬季风速分别在10:00、12:00开始逐渐增加,在20:00、21:00后开始快速减小,夏季风向基本稳定,冬季风向在15:00存在突变,风攻角与风速、风向显著相关,在冬季先减后增、15:00取最大负值,夏季相反;冬季风速剖面显著变化、夏季趋于平稳,指数律模型不能准确描述峡谷风速的垂直分布规律;夏季紊流强度趋于平稳,冬季先减后增、12:00取最小值,实测横风向、竖向紊流强度与顺风向比值高于规范推荐值;冬季、夏季紊流积分尺度变化趋势相同且与风速变化趋势一致,实测积分尺度远小于规范推荐值;归一化功率谱峰值频率随时间变化先减后增,功率谱可采用统一形式进行描述,并考虑其在频域内分布随季节、时间改变产生的偏移效果。

白鹤滩水电站干季偏北大风环流形势分析和客观判识

基于2018—2020年11月至次年4月金沙江下游峡谷区139次干季偏北大风天气个例开展大风天气环流形势的分析,并参考Lamb-Jenkinson方法建立客观判识条件,并对判识条件进行检验和修正。获得以下结论:选择水电站15次典型偏北大风天气,通过对环流形势特征分析,将影响大风的高空环流概括为:南支槽型、高原槽型和横槽型。15次个例中南支槽型和高原槽型均出现了6次,横槽型出现了3次。基于Lamb-Jenkinson方法的环流特征参数分析,确定了干季大风环流客观判识的关键区和初步判识条件。南支槽型和高原槽型判识条件为关键区地转风纬向分量u>10 dagpm/10°(经度),且与经向分量v的差(u-v)>10 dagpm/10°(经度),同时地转涡度ξ>0 dagpm/10°;横槽型判识条件为关键区u<20 dagpm/10°(经度),且要求ξ>u。另选取2021年干季14次大风个例检验以上环流判识条件,发现有11次准确识别出环流类型。根据未识别出环流类型的原因,对u和u-v的阈值进行修正,结果表明修正后的判识条件准确可行。最终建立的环流形势客观判识方法可为白鹤滩水电站大风预警提供参考。

基于三维仿真的四季气候变化对矿井通风影响规律研究

四季气候变化影响着矿井内自然风压的大小和方向,若将自然风压作为动力合理运用,有益于矿井通风系统节能减排。眼前山铁矿井下通风系统在初期设计中对自然风压的利用较少,且风机选型方面未将四季气候变化的因素考虑其中。本文对眼前山地区四季气候变化对矿井通风的影响规律进行研究,并以此规律指导井下基站风机进行优化。通过三维仿真系统建立井下通风系统模型,模拟眼前山地区一年四季气候条件,通过风流模拟计算进风井口处的自然风压大小和方向,结果表明眼前山地区夏季日间,1号主进风井、2号主进风井处会出现与矿井通风方向反向的自然风压,其余季节进风井处自然风压均有利于通风,其中,冬季自然风压可利用价值最大,且冬季风机风压较夏季风机风压显著增大,使得冬季总进风量增加4.46%;建议针对主机站2-3基站、2-4基站的K-8-19型风机和主机站2-15基站、2-16基站的K-8-23型风机进行工况点调节,在冬季时期将主扇叶片安装角由35°调整至30°;根据眼前山地区的四季气候变化规律适时调整主要通风机工况点,对自然风压有效利用,解决了矿井通风系统冬季风量过剩的问题,实现了以更加节能的方式满足矿井通风需要。

汛期水风光多能互补动态调度模型研究

为充分利用水电站水库汛期在预报无洪水或小洪水时的调节能力,将汛期运行水位动态控制域对应库容作为调节风光运行的可用库容,在提高水库调节能力的基础上给出了考虑入库洪水实时状态的汛期水电站水库动态消纳风光调度模式,以风光出力期望值加水电出力之和与负荷偏差最小为目标,结合风光出力不确定性建立了汛期水风光多能互补动态调度模型,并以福建省水口水电站为例进行模拟调度计算。结果表明:所提动态消纳风光调度模式能够在保证防洪安全的前提下充分合理利用水位动态控制域内的调节能力来调节风光出力,使失负荷时段数和发电量缺口期望值相较于传统调度模式分别降低约37%和32%,水电站水库平均发电水头提高约4.39%,不仅可提高系统出力可靠性,且能增加系统运行效益。研究成果可为汛期调节风光出力提供参考。

计及季度趋势变时间步长风速仿真模型及应用

为提高风电并网系统充裕度评估精度,提出计及季度趋势的变时间步长风速仿真模型。该模型应用奇异谱分析从风速样本中提取季度趋势和随机波动分量,应用线性插值和奥恩斯坦-乌伦贝克过程对两分量建模,产生任意时间步长的仿真风速样本。将该模型嵌入蒙特卡罗模拟法,提出风电并网系统的季度充裕度评估方法。应用该模型仿真某观测站风速样本,评估风电并网IEEE-RTS发电系统的季度充裕度,结果表明,该模型可产生与实测风速样本统计指标等特征接近的任意时间步长仿真风速样本,且季度充裕度评估精度较高。

风场对鄱阳湖丰水期表层蓝藻密度的影响

目前,在风场对蓝藻的影响研究方面,国内针对太湖、滇池、巢湖等浅水湖泊的研究较多,针对鄱阳湖的研究则多集中于蓝藻群落特征及其与营养盐之间的关系。近年来,作为长江流域重要的通江湖泊,处于轻度富营养化状态的鄱阳湖水体蓝藻水华在局部库湾和部分水域出现,风场如何影响鄱阳湖表层蓝藻密度是一个值得探讨的问题。20192021年,在鄱阳湖布设13~49个采样点,于平水期、丰水期和枯水期现场采集各个点位表层水样、藻类、风场和流场数据,分析风场对鄱阳湖丰水期表层蓝藻密度的影响。结果表明,20192021年鄱阳湖丰水期风速与表层蓝藻密度呈显著正相关性,风场对水体的充分混合及驱动水体形成的风生流是促进蓝藻生长的原因之一。在流速较高(>0.05 m/s)的区域,无论风速高于还是低于临界风速(3~4 m/s),鄱阳湖表层蓝藻密度的空间分布受流场的影响更大;在流速较低(<0.05 m/s)的区域,风速在临界风速以下时,鄱阳湖表层蓝藻密度的空间分布受风场影响更大。20192021年鄱阳湖丰水期蓝藻密度超过水华暴发的阈值,但在高风速高流速的共同作用下未能发生大范围的蓝藻水华,仅能在风速适宜(<3~4 m/s)、流速较低(<0.05 m/s)的内湾、尾闾区等区域发生小面积的蓝藻水华。鄱阳湖丰水期水体处于长江顶托的低流速且微风条件下时,发生大面积蓝藻水华的概率可能会明显上升。

基于工业余热与可再生能源耦合的赤峰市低碳供热研究

以赤峰市大温差供热工程实践为例,介绍了赤峰市低碳供热方案的设计理念和实施步骤。从赤峰市供热热源紧缺,城区周边电厂乏汽余热、工业余热和弃风电力转化热量潜力估算,降低一次网回水温度必要性,大温差供热推进和分阶段实施过程,各阶段热平衡等5个方面进行了详细说明。根据规划,至2035年赤峰市中心城区供热热量来源于非供暖季储存弃风电力转化热量和工业余热,以及供暖季工业余热和燃煤调峰电厂热量,单位供热面积的二氧化碳排放强度是现状的1/30。

Response of the cold water mass in the western South China Sea to the wind stress curl associated with the summer monsoon

Analysis of climatological observation temperature data reveals that during the southwesterly monsoon, there exists a low tempera- ture zone east of Vietnam. It cools down from June to August and warms up in September. Meanwhile, during this period, the cold water mass spreads eastward to the deep basin. Numerical experiments validate the results of data analysis and further verify that there are two basic factors that induce the Vietnam cold water. The major one is the strong local positive wind stress curl, which leads to the divergence of sea surface water and the upward supplement of lower layer water in the deep basin. Another minor one is the alongshore component of southwesterly monsoon, which drives the offshore Ekman transport and coastal upwelling in the shallow region along the Vietnam coast. In addition, the negative wind stress curl in the southern South China Sea inputs negative vorticity to the ocean and drives a strong anticyclonic gyre, which affects the spatial distribution of the cold water evidently.

Seasonal variations of the near surfacelayer parameters over the Antarctic ice sheet in Princess Elizabeth Land,East Antarctica

Analysis of sensible heat flux （ Qh ）, latent heat flux （ Qe ）, Richardson number （Ri） ,bulk transport coefficient （Cd） and katabatic windsare presented by using the meteorological data in the near surface layer from an automatic weather station （AWS） in Princess Elizabeth Land, East Antarctica ice sheet and the data of corresponding period at Zhongshan station in 2002. It shows that annual mean air temperature at LGB69 is -25.6℃, which is 16.4℃ lower than that at Zhongshan, where the elevation is lower and located on the coast. The temperature lapse rate is about 1.0℃/110 m for the initial from coast to inland. The turbulence heat flux at LGB69 displays obvious seasonal variations with the average sensible heat flux -17.9 W/m^2 and latent heat flux -0.9 W/m^2. The intensity （Qh ＋ Qe ） of coolling source is - 18.8 W/m^2 meaning the snow surface layer obtains heat from atmosphere. The near surface atmosphere is near-neutral stratified with bulk transport coefficients （Cd） around 2.8 ×10^-3 ,and it is near constant when the wind speed higher than 8 m/s. The speed and the frequency of easterly Katabatic winds at LGB69 were higher than that at Zhongshan Station.

Characteristics and possible causes of the seasonal sea level anomaly along the South China Sea coast

Based on sea level, air temperature, sea surface temperature（SST）, air pressure and wind data during 1980–2014,this paper uses Morlet wavelet transform, Estuarine Coastal Ocean Model（ECOM） and so on to investigate the characteristics and possible causes of seasonal sea level anomalies along the South China Sea（SCS） coast. The research results show that：（1） Seasonal sea level anomalies often occur from January to February and from June to October. The frequency of sea level anomalies is the most in August, showing a growing trend in recent years. In addition, the occurring frequency of negative sea level anomaly accounts for 50% of the total abnormal number.（2） The seasonal sea level anomalies are closely related to ENSO events. The negative anomalies always occurred during the El Ni？o events, while the positive anomalies occurred during the La Ni？a（late El Ni？o） events. In addition, the seasonal sea level oscillation periods of 4–7 a associated with ENSO are the strongest in winter, with the amplitude over 2 cm.（3） Abnormal wind is an important factor to affect the seasonal sea level anomalies in the coastal region of the SCS. Wind-driven sea level height（SSH） is basically consistent with the seasonal sea level anomalies. Moreover, the influence of the tropical cyclone in the coastal region of the SCS is concentrated in summer and autumn, contributing to the seasonal sea level anomalies.（4） Seasonal variations of sea level, SST and air temperature are basically consistent along the coast of the SCS, but the seasonal sea level anomalies have no much correlation with the SST and air temperature.

Seasonal variation of the surface North Equatorial Countercurrent (NECC) in the western Pacific Ocean

The North Equatorial Countercurrent(NECC) is an important zonal fl ow in the upper circulation of the tropical Pacifi c Ocean, which plays a vital role in the heat budget of the western Pacifi c warm pool. Using satellite-derived data of ocean surface currents and sea surface heights(SSHs) from 1992 to 2011, the seasonal variation of the surface NECC in the western tropical Pacifi c Ocean was investigated. It was found that the intensity(INT) and axis position(Y_(CM)) of the surface NECC exhibit strikingly different seasonal fl uctuations in the upstream(128°–136°E) and downstream(145°–160°E) regions. Of the two regions, the seasonal cycle of the upstream NECC shows the greater interannual variability. Its INT and Y CM are greatly infl uenced by variations of the Mindanao Eddy, Mindanao Dome(MD), and equatorial Rossby waves to its south. Both INT and YC M also show semiannual signals induced by the combined effects of equatorial Rossby waves from the Central Pacifi c and local wind forcing in the western Pacifi c Ocean. In the downstream region, the variability of the NECC is affected by SSH anomalies in the MD and the central equatorial Pacifi c Ocean. Those in the MD region are especially important in modulating the Y CM of the downstream NECC. In addition to the SSH-related geostrophic fl ow, zonal Ekman fl ow driven by meridional wind stress also plays a role, having considerable impact on INT variability of the surface NECC. The contrasting features of the variability of the NECC in the upstream and downstream regions refl ect the high complexity of regional ocean dynamics.

Preliminary Study on the Distribution of Meridional Wind in Near Space

Based on high-altitude wind data in about one year, the seasonal changes and vertical profiles of meridional wind in near space were studied, and the reasons for the increase of meridional wind in spring and winter were analyzed. Meanwhile, the seasonal distribution of atmospher- ic circulation in the stratosphere was studied, and the seasonal changes and mechanism of wind conversion from the east to the west were re- vealed. The results show that the speed of meridional wind in near space was the highest in spring, followed by autumn and winter, while it was the lowest in summer; the increase of meridional wind in spring and winter was related to weather systems in the troposphere, such as the development of strong warm ridge over Xinjianq and cold trouclh system, and the svstem resulted in the increase of meridional wind.

Spatio-temporal variability in sea surface wind stress near and off the east coast of Korea

Sea surface wind stress variabilities near and off the east coast of Korea, are examined using 7 kinds of wind datasets from measurements at 2 coastal (land) stations and 2 ocean buoys,satellite scatterometer (QuikSCAT), and global reanalyzed products (ECMWF,NOGAPS,and NCEP/NCAR). Temporal variabilities are analyzed at 3 frequency bands; synoptic (2-20 d), intra-seasonal (20-90 d),and seasonal (>90 d).Synoptic and intra-seasonal variations are predominant near and off the Donghae City due to the passage of the mesoscale weather system. Seasonal variation is caused by southeastward wind stress during Asian winter monsoon. The sea surface wind stress from reanalyzed datasets.QuikSCAT and KMA-B measurements off the coast show good agreement in the magnitude and direction,which are strongly aligned with the alongshore direction.At the land-based sites,wind stresses are much weaker by factors of 3-10 due to the mountainous landmass on the east parts of Korea Peninsula.The first EOF modes(67%-70%) of wind stresses from reanalyzed and QuikSCAT data have similar structures of the strong southeastward wind stress in winter along the coast but show different curl structures at scales less than 200 km due to the orographic effects.The second EOF modes (23%-25%) show southwestward wind stress in every September along the east coast of the North Korea

IMPACT OF SSTA OF SOUTHERN HEMISPHERE ON FLOOD SEASON PRECIPITATION ANOMALIES IN YUNNAN

Based on the reanalysis data of monthly mean global SST and wind from the NCEP/NCAR and the observation data of rain seasons in 124 stations of Yunnan province from 1961 to 2006, we applied the analytical methods of correlation analysis and composite analysis and a significance testing method to two sets of samples of average differences. The goal is to investigate into the influence of the Southern Hemispheric(SH) SST on the summer precipitation in Yunnan from January to May so as to identify the key time and marine regions. Physical mechanisms are obtained by analyzing the influence of sea level wind and the key marine regions on the precipitation during Yunnan's rain season.Results show that there is indeed significant relationship between the SST in SH and summer precipitation in Yunnan.The key areas for influencing the summer precipitation are mainly distributed in a region called "West Wind Drift" in the SH, including the Southeast Indian, southern Australia, west coast of eastern Pacific off Chile, Peru and the southwest Atlantic Magellan. Besides, the most significant marine region is the west coast of Chile and Peru(cold-current areas of the eastern Pacific). Diagnostic analysis results also showed that monsoons in the Bay of Bengal, a cross-equatorial flow in the Indian Ocean near the equator and southwest monsoon in India weaken during the warm phase of the Peruvian cold current in the eastern Pacific. Otherwise, they strengthen.

Seasonal variation in dust events and the causes of the variation in the Tarim Basin,China

We analyzed dust event occurrence and its seasonal distribution at 16 sites in the Tarim Basin,China.Although the overall frequency of dust events was the highest in spring in this region,its variation in other seasons could be classified into three patterns:(1) frequency of dust events in autumn > that in summer > that in winter(at the Kashi and Kuche sites);(2) frequency in summer > that in winter > that in autumn(at the Ruoqiang site);and(3) frequency in summer > that in autumn > that in winter(at all other areas of the Tarim Basin).The frequency of dust events and their seasonal variations in the Tarim Basin were mainly controlled by wind speed and locally available dust sources;the former was the key control when dust sources did not differ significantly.The seasonal variation in evaporation had a smaller,but still significant effect on the frequency of dust events.