气象因子和海风对秦皇岛市臭氧污染的影响     

周士茹  宋金妹  陆倩  郭鸿鸣  赵玉广  高艳春 《气象与环境学报》2021,37(2):64-70

利用2017年9月至2019年9月秦皇岛市环境监测站污染物浓度资料以及秦皇岛市国家基本气象站和浮标站的气象数据,统计分析了秦皇岛市O₃污染特征以及气象因子和海风对秦皇岛市O₃污染的影响。结果表明：秦皇岛市O₃污染月变化特征表现为以5—6月和9月最为严重,10—12月和1—2月则无O₃超标天气出现。O₃污染的日变化特征表现为单峰型分布,午后O₃浓度最高而清晨O₃浓度最低。有利于秦皇岛市出现O₃污染的气象条件为太阳辐射强度850—950 W·m^-2、日最高气温高于32℃、无降水和相对湿度50%—60%、受SW和SSW风影响。秦皇岛市海风以6—8月最多,出现频率达50%以上,海风多在上午08—10时开始出现,午后12—15时达到最大,傍晚以后减弱结束;5—6月和8—9月有海风日的O₃-8h平均浓度均高于无海风日,且5月、6月和9月有海风日的O₃-8h月平均浓度高达155—166 μg·m^-3,海陆风环流对秦皇岛市的O₃污染有加重的影响。  相似文献   

盛夏杭州湾一次海风锋触发雷暴的数值模拟分析          下载免费PDF全文

吴福浪  李晓丽  於敏佳  张晶晶  刘耀杰 《大气科学学报》2019,42(4):581-590

利用常规气象观测资料、多普勒气象雷达资料、浙江省自动站加密资料、NCEP/FNL再分析资料,结合高分辨率中尺度数值模式WRF对杭州湾地区2016年7月28日一次海风锋触发雷暴天气的发生、发展演变特征进行数值模拟。结果表明:1)海风锋是此次强雷暴天气过程的主要触发系统。2)中尺度模式WRF较好地模拟出此次雷暴过程的降水和低层风场、温度场分布以及海风锋水平垂直结构。3)海风锋对局地比湿及涡度特征的加强有明显的促进作用,为雷暴的发生发展提供有利的水汽和动力条件。4)分析对流参数演变曲线的突变位置,对雷暴发生的时间有一定的指示和预报意义,杭州湾南侧单纯的海风锋也可以触发雷暴的发生发展。  相似文献   

The Kwinana Coastal Fumigation Study: II – Growth of the Thermal Internal Boundary Layer     

A. K. Luhar  B. L. Sawford  J. M. Hacker  K. N. Rayner 《Boundary-Layer Meteorology》1998,89(3):385-405

Aircraft measurements of potential temperature and turbulent kinetic energy are used to examine the growth of the thermal internal boundary layer (TIBL) in sea-breeze flows on four selected days of a coastal fumigation study performed in 1995 at Kwinana in Western Australia. The aircraft data, together with radiosonde measurements taken on the same days, show a multi-layered low-level onshore flow in the vertical with a superadiabatic layer extending to about 50 m above the water surface on all four days. On the first three days the layer above the superadiabatic layer was neutral, typically 200 m deep, capped by a stably stratified region, whereas on the remaining day it was fully stable. The occurrence of the neutral layer on most experimental days contrasts with the more usual situation involving an entirely stable onshore flow. A composite approach based on both temperature and turbulence data is used to provide a pragmatic but self-consistent definition of the TIBL height. The data for the first three days indicate that the TIBL grows rapidly into the neutrally stratified region to the top of the region within about 2 km from the coast, with a very slow subsequent growth into the stable stratification aloft. On the other hand, the TIBL grows only to about 200 m within a distance of 7 km from the coast on the fourth day due to a strong stable stratification.An existing numerical TIBL model based on the slab approach, capable of describing the TIBL growth in both neutral and stable environments, and a recent analytical model, more efficient for operational use, are used to simulate the aircraft TIBL observations. The predictions by both models agree reasonably well with the data.  相似文献   

Inland and Offshore Propagation Speeds of a Sea Breeze from Simulations and Measurements   总被引：1，自引：1，他引：0  

Klara Finkele 《Boundary-Layer Meteorology》1998,87(2):307-329

The inland and offshore propagation speeds of a sea breeze circulation cell are simulated using a three-dimensional hydrostatic model within a terrain-following coordinate system. The model includes a third-order semi-Lagrangian advection scheme, which compares well in a one-dimensional stand-alone test with the more complex Bott and Smolarkiewicz advection schemes. Two turbulence schemes are available: a local scheme by Louis (1979) and a modified non-local scheme based on Zhang and Anthes (1982). Both compare well with higher-order closure schemes using the Wangara data set for Day 33–34 (Clark et al., 1971).Two-dimensional cross-sections derived from airborne sea breeze measurements (Finkele et al. 1995) constitute the basis for comparison with two-dimensional numerical model results. The offshore sea breeze propagation speed is defined as the speed at which the seaward extent of the sea breeze grows offshore. On a study day, the offshore sea breeze propagation speed, from both measurements and model, is -3.4 m s^-1. The measured inland propagation speed of the sea breeze decreased somewhat during the day. The model results show a fairly uniform inland propagation speed of 1.6 m s^-1 which corresponds to the average measured value. The offshore sea breeze propagation speed is about twice the inland propagation speed for this particular case study, from both the model and measurements.The influence of the offshore geostrophic wind on the sea breeze evolution, offshore extent and inland penetration are investigated. For moderate offshore geostrophic winds (-5.0 m s^-1), the offshore and inland propagation speeds are non-uniform. The offshore extent in moderate geostrophic wind conditions is similar to the offshore extent in light wind conditions (-2.5 m s^-1). The inland extent is greater in light offshore geostrophic winds than in moderate ones. This suggests that the offshore extent of the sea breeze is less sensitive to the offshore geostrophic wind than its inland extent. However, these results hold only if it is possible to define an inland propagation speed. For stronger offshore geostrophic winds (-7.5 m s^-1), the sea breeze is completely offshore and the inland propagation speed is ill-defined.  相似文献   

NUMERICAL EXPERIMENTS ON THE TIBL PROFILES AND THE LOCAL SEA BREEZE CIRCULATION IN COASTAL AREAS     

王卫国  蒋维楣 《热带气象学报(英文版)》1998,4(1):72-78

A two-dimensional nonlinear PBL numerical model using an energy closure (E-ε)method has been employed to study the sea breeze circulation and TIBL in coastal areas. The main characteristics of sea breeze obtained from numerical experiments agree with those from general observation facts. The depth of sea breeze ranges from 300 to 900 meters, maximum velocity from 1.5 m/s to 4 m/s, and its height from 100 m to 300 m. The agreement between comparisons reveals that the performance of the model is good, and the selected experiment conditions are reasonable. This paper refits the function of TIBL profiles using the Weisman's formula and the exponent value is considered to change with the different states of sea breeze. Numerical experiment results indicate that the exponent of the TIBL profile, ranging from 0.4 to 1.1, is related to the strength and depth of the sea breeze. The exponent of 0.5 is suitable only when sea breeze is fully developed. This paper also gives various exponents under different sea breezes.  相似文献   

渤海湾北岸海陆风及湍流强度特征分析          下载免费PDF全文

龙强  王锋  王畅  米欣悦 《应用海洋学学报》2020,39(3):303-311

利用渤海湾北岸祥云岛岸基站2017—2018年观测数据和两座梯度测风塔2011—2013年观测资料分别分析了当地海陆风和湍流强度特征,并重点对不同天气系统所致大风条件下的湍流强度特点做了剖析。结果表明:渤海湾北岸海陆风特征明显,昼夜风向主要由SSW向ENE转变,夏季昼夜风向转换尤为显著。整体而言,风速和湍流强度随高度增大分别呈增大、减小趋势,且近海面层湍流强度小于近地层湍流强度。湍流强度具有显著的季节性特征,夏季大、冬季小、春秋季变化不明显,且近海面层湍流强度相对近地层变化平缓。近海面层70 m及以下湍流强度在偏东大风条件下反而比近地层湍流强度大,雷雨大风期间近海面层和近地层均出现湍流强度随高度增大而增大、风速随高度增大而减小的特殊情况,台风靠近风塔时各层风速显著增大、湍流强度变化不明显,但台风中心到达时湍流强度迅速增至峰值,二者时间一致并早于风速最小值出现时间约1 h。近海面层和近地层有8%～10%样本的湍流强度超出了IEC-61400设计标准,建议渤海湾北岸风力发电风机抗湍流参数调整至0. 43～0. 49。  相似文献   

临太湖局地平原区人居环境的自然适宜性评价——以吴江区为例          下载免费PDF全文

郭云飞  包云轩  严明良  沈利洪  朱焱 《气象科学》2023,43(4):543-552

本文以苏州市吴江区为例,利用1971—2016年吴江区常规气象观测资料、2004—2016年吴江区自动气象观测数据、2016年吴江区各镇人口和面积数据、2016年ASTER GDEM 高程数据和Landsat 8 OLI_TIRS卫星遥感数据,将湖陆风指数引入人居自然环境适宜性评价体系,建立缓冲区后,分别计算气候适宜性指数、地被指数、水文指数、湖陆风指数和人居环境自然适宜性综合指数,在此基础上,分区分级评价了吴江区人居环境的自然适宜性。研究结果表明:(1)吴江区人居环境自然适宜度从西部往东部逐渐递减。(2)一般适宜区主要位于吴江区的东北部和东南局地,中度适宜区分布在中北部和南部,较高适宜区位于中部以西太湖沿岸,高度适宜区位于紧临太湖的西南地区,极高适宜区位于西南角局部地区。(3)引入湖陆风指数后,评价结果能更好地反映临湖平原的湖陆风环流对局地气候所起的关键作用。(4)建立缓冲区后的水文指数分布能够更客观地反映吴江区不同尺度水体分布对人居环境自然选择的影响。  相似文献   

城市下垫面对渤海湾海风锋特征影响的一次数值试验     

梁钊明  高守亭  王东海  王彦 《大气科学》2013,37(5):1013-1024

海风锋与沿海强对流天气密切相关,而城市化发展对沿海地区下垫面的改变会对海风锋特征产生影响。鉴于此,本文利用耦合了新一代城市物理方案UCP-BEM(Urban Canopy Parameterization-Building Energy Model)的WRF(Weather Research and Forecasting)模式开展数值试验分析了城市下垫面对渤海湾海风锋特征的影响。结果显示:城市下垫面高粗糙度对低层海风风速的明显削弱造成海风锋往内陆推进距离稍减,低层辐合和上升运动减弱;城市下垫面较大的向上感热通量和较小的向上水汽通量以及高粗糙度对海风的削弱的共同作用造成冷湿海风对低层大气的降温和增湿幅度减弱;高粗糙度的城市下垫面对海风环流的摩擦力效应使得海风得到抬升,这导致了冷湿海风对低层大气的降温和增湿的垂直范围得到提升;受这些结果影响,海风锋背后低层有效位能减小,但垂直分布范围扩大,从而造成对流抑制高值区抬升,同时海风锋背后的静力不稳定区变厚,其上面的动力不稳定区则变薄,但不稳定区总厚度基本不变。  相似文献   

Characteristics of sea breeze front development with various synoptic conditions and its impact on lower troposphere ozone formation     

Hyo-Eun JI  Soon-Hwan LEE  Hwa-Woon LEE 《大气科学进展》2013,30(5):1461-1478

To examine the correlation between the sizes of sea breeze fronts and pollutants under the influence of synoptic fields, a numerical simulation was conducted in the southeast coastal area of the Korean Peninsula, where relatively high concentrations of pollutants occur because of the presence of various kinds of industrial developments. Sea breeze and sea breeze front days during the period 2005-09 were identified using wind profiler data and, according to the results, the number of days were 72 and 53, respectively. When synoptic forcing was weak, sea breeze fronts moved fast both in horizontal fields and in terms of wind velocity, while in the case of strong synoptic forcing, sea breeze fronts remained at the coast or moved slowly due to strong opposing flows. In this case, the sea breeze front development function and horizontal potential temperature difference were larger than with weak synoptic forcing. The ozone concentration that moves together with sea breeze fronts was also formed along the frontal surfaces. Ozone advection and diffusion in the case of strong synoptic forcing was suppressed at the frontal surface and the concentration gradient was large. The vertical distribution of ozone was very low due to the Thermal Internal Boundary Layer (TIBL) being low.  相似文献   

宁波地区海-陆下垫面差异对雷暴过程影响的数值模拟   总被引：2，自引：0，他引：2  

汪雅  苗峻峰  谈哲敏 《气象学报》2013,71(6):1146-1159

利用耦合Noah陆面过程的WRF模式对2009年6月5日傍晚发生在宁波地区的一次雷暴过程进行数值模拟,通过改变下垫面覆盖类型的敏感性试验,探讨了海洋和陆地下垫面对雷暴过程的影响。结果表明,WRF模式能够较合理地模拟出雷暴的发生、发展过程。雷暴发生前期,由于海-陆强烈的热力差异,海风特征明显,海风引起的抬升运动触发了雷暴,海风形成的强辐合区对应雷暴过程累积降水量的大值区。当研究区域全部被替换成陆地后,地表的粗糙度增大,在研究区域东部由于摩擦辐合加强,产生了强烈的上升运动,多个发展旺盛的对流单体在上升运动区生成,使雷暴产生的降水区域东扩、降水量增大、雷暴维持时间延长。当研究区域所有陆地被替换成水体后,白天地表通量减小,大气边界层中湍流运动减弱,边界层高度降低,大气层结变得稳定,不利于对流发展。  相似文献