卫星高光谱大气CO2探测精度验证研究进展   总被引：2，自引：0，他引：2  

张兴赢  孟晓阳  周敏强  白文广  周丽花  胡玥明  余骁 《气候变化研究进展》2018,14(6):602-612

卫星高光谱大气CO₂遥感探测对全球气候变化研究意义重大,卫星CO₂反演产品的地基观测验证是获得产品精度评价、发现算法可适用范围和局限性的重要环节,因此地基高光谱CO₂的观测验证研究对提高卫星产品定量精度至关重要。本文综述了当前国际上大气CO₂探测卫星的研制进展,短波红外大气CO₂的反演方法进展,重点阐述了地基高光谱CO₂探测技术进展及其对卫星大气CO₂的定量探测精度验证方法和技术研究进展,并对该研究领域未来的发展提出展望。  相似文献   

“5.7”广州局地突发特大暴雨中尺度特征及成因分析   总被引：7，自引：0，他引：7  

徐珺  毕宝贵  谌芸  陈涛  宫宇  李嘉睿 《气象学报》2018,76(4):511-524

2017年5月7日广州局地突发特大暴雨,降水集中爆发于广州北部复杂地形区,单点小时雨量大、强降雨持续时间长。然而降水发生于副热带高压边缘、无明显的低空急流等天气系统配合,为弱强迫背景下的华南前汛期暴雨,加之珠三角地形复杂,其触发和组织维持机制等问题引起了气象科研和预报工作者的广泛关注。针对其降水特点,采用5 min自动气象站观测、分钟雨量、风廓线雷达、葵花8号气象卫星红外等高时空分辨率观测数据探讨中尺度对流系统的触发和组织维持过程,发现:中纬度入海高压南侧偏东风和低层切变系统为珠三角边界层南风风速辐合提供了有利的天气背景,喇叭口地形增强了风速辐合。小尺度地形辐射降温配合城市热岛在山前形成高温度梯度区,山风与南风对峙使地面辐合线在山前移速变慢有助于热带云团的生成。地形阻挡抬升和高温度梯度加强上升运动,南风风速脉动使云团迅速向山前移动,最终对流爆发。以暖云降水为主的对流系统产生弱冷池驱动对流系统连续传播,使强降水回波面积增大并在小尺度地形影响下稳定位于增城附近,产生极端小时雨强;中尺度对流系统的单体移动方向和传播方向近乎相反导致系统移动非常缓慢,后向传播明显,最终导致长时间强降水。   相似文献   

不同云重叠参数对全球和东亚地区模拟总云量的影响     

王海波  张华  荆现文  谢冰 《气象学报》2018,76(5):767-778

在国家气候中心全球大气环流模式BCC_AGCM2.0中引入一组基于CloudSat/CALIPSO卫星观测的、能够体现真实时空变化特征的云垂直重叠参数（抗相关厚度,L_cf）数据,以减小由云的重叠描述造成的辐射场的不确定性。对比了采用时空变化的云重叠参数和采用恒定云重叠参数的气候模拟结果,发现无论在全球还是东亚区域,采用基于卫星观测的云重叠参数对模拟的总云量都有一定程度的改进。采用时空变化的云重叠参数后,冬、夏两季全球平均总云量与云和地球的辐射能量系统（CERES）卫星资料的误差都减少了1.6%,其中热带对流区域总云量的正偏差和副热带地区总云量的负偏差都明显减少,这些有助于正确模拟不同区域间的能量收支差异。在东亚区域,采用时空变化的云重叠参数后,冬、夏两季的东亚区域平均总云量与CERES卫星资料的误差分别减少了1.8%和1.4%。综上所述,基于CloudSat/CALIPSO卫星资料计算得到的L_cf有助于改进大气环流模式对总云量的模拟,从而提高模式对辐射场的模拟精度。   相似文献   

Influences of the Internal Mixing of Anthropogenic Aerosols on Global Aridity Change     

Hua Zhang  Chen Zhou  Shuyun Zhao 《Acta Meteorologica Sinica》2018,32(5):723-733

Influences of the mixing treatments of anthropogenic aerosols on their effective radiative forcing (ERF) and global aridity are evaluated by using the BCC_AGCM2.0_CUACE/Aero, an aerosol–climate online coupled model. Simulations show that the negative ERF due to external mixing (EM, a scheme in which all aerosol particles are treated as independent spheres formed by single substance) aerosols is largely reduced by the partial internal mixing (PIM, a scheme in which some of the aerosol particles are formed by one absorptive and one scattering substance) method. Compared to EM, PIM aerosols have much stronger absorptive ability and generally weaker hygroscopicity, which would lead to changes in radiative forcing, hence to climate. For the global mean values, the ERFs due to anthropogenic aerosols since the pre-industrial are–1.02 and–1.68 W m^–2 for PIM and EM schemes, respectively. The variables related to aridity such as global mean temperature, net radiation flux at the surface, and the potential evaporation capacity are all decreased by 2.18/1.61 K, 5.06/3.90 W m^–2, and 0.21/0.14 mm day^–1 since 1850 for EM and PIM schemes, respectively. According to the changes in aridity index, the anthropogenic aerosols have caused general humidification over central Asia, South America, Africa, and Australia, but great aridification over eastern China and the Tibetan Plateau since the pre-industrial in both mixing schemes. However, the aridification is considerably alleviated in China, but intensified in the Arabian Peninsula and East Africa in the PIM scheme.  相似文献   

Water Vapor Transport Related to the Interdecadal Shift of Summer Precipitation over Northern East Asia in the Late 1990s     

Po Hu  Minghao Wang  Liu Yang  Xiaojuan Wang  Guolin Feng 《Acta Meteorologica Sinica》2018,32(5):781-793

In this study, an interdecadal shift of summer precipitation over northern East Asia (NEA) was identified, demonstrating that summer precipitation decreased abruptly after 1998/99. The synchronous shift in summer moisture budget and water vapor transport over NEA was further investigated by using the NCEP/NCAR reanalysis data. The results indicate that water vapor transported northward into NEA from three low-latitude paths was limited because most water vapor was transported eastward. Water vapor transported from the westerly path in mid–high (WMH) latitudes exhibited significant correlations with summer precipitation in NEA and experienced a significant adjustment in the late 1990s. Regarding the spatial distributions of water vapor transport, less input was found through the western boundary while more output occurred through the eastern boundary of NEA, and zonal water vapor transport fluxes mainly concentrated at the low to middle levels, which led to the summer precipitation shift in NEA around the late 1990s. Furthermore, it is also confirmed that the wind anomalies (rather than the moisture disturbance) as the dominant internal dynamic factor and Pacific Decadal Oscillation/Atlantic Multidecadal Oscillation (PDO/AMO) as possible external force played important roles in influencing the water vapor transport and causing the summer precipitation shift over NEA in the late 1990s.  相似文献   

The 200-hPa Wind Perturbation in the Subtropical Westerly over East Asia Related to Medium-Range Forecast of Summer Rainfall in China     

Ronghua Jin  Yan Li  Qingrou Long  Sijia Liu 《Acta Meteorologica Sinica》2018,32(3):491-502

The 200-hPa wind perturbation (WP) in the subtropical westerly over East Asia (SWEA) has seldom been examined in previous studies, especially in connection with forecast of the summer rainfall in China. Based on the daily NCEP/NCAR reanalysis data and precipitation observations in China from 1 June to 31 August of 1960–2015, this study first systematically analyzes the spatiotemporal distribution features of the 200-hPa WP in the SWEA on different scales, especially during the Meiyu season in the Yangtze–Huaihe region and during the rainy period in North China, by using spectral decomposition and period analysis. It is found that in the 56-yr mean fields, the 200-hPa WP in the SWEA is collocated with the East Asian subtropical jet (EASJ), with the centers of the two systems coincidentally overlapped. The WP filed in the subtropical westerly mainly comprises planetary- and synoptic-scale waves. The quasi-stationary planetary-scale wave seems to determine the shape and intensity of the WP in the SWEA, while the synoptic-scale wave is closely related to the local central intensity of the WP. The daily evolution of the 56-yr mean fields shows that, following the northward (southward) movement of SWEA from 1 June to 31 August, the planetaryscale WP in the SWEA becomes gradually weakened (intensified) whereas the synoptic-scale WP is slightly intensified (weakened).The results also reveal that during the Meiyu season in the Yangtze–Huaihe region, the WP in the SWEA moves northward slowly around 37°–39°N, demonstrating a quasi-biweekly oscillation in its geographic location, which is largely attributed to the strong (weak) planetary-scale (synoptic-scale) component. On the contrast, in the summer rainy season over North China, the WP in the SWEA further strives northward beyond 40°N, showing both quasi-biweekly and weekly oscillations in its position; meanwhile, the planetary-scale wave in the SWEA becomes weakened whereas the synoptic-scale wave is enhanced. These salient variational features of the WP in the SWEA and its scaledependent components may be useful for the medium-range forecast of the rain belt migration in eastern China.  相似文献   

Changes in Extreme Maximum Temperature Events and Population Exposure in China under Global Warming Scenarios of 1.5 and 2.0°C: Analysis Using the Regional Climate Model COSMO-CLM     

Mingjin?Zhan  Xiucang?Li  Hemin?Sun  Jianqing?Zhai  Tong?Jiang  Yanjun?WangEmail author 《Acta Meteorologica Sinica》2018,32(1):99-112

We used daily maximum temperature data (1986–2100) from the COSMO-CLM (COnsortium for Small-scale MOdeling in CLimate Mode) regional climate model and the population statistics for China in 2010 to determine the frequency, intensity, coverage, and population exposure of extreme maximum temperature events (EMTEs) with the intensity–area–duration method. Between 1986 and 2005 (reference period), the frequency, intensity, and coverage of EMTEs are 1330–1680 times yr^–1, 31.4–33.3°C, and 1.76–3.88 million km², respectively. The center of the most severe EMTEs is located in central China and 179.5–392.8 million people are exposed to EMTEs annually. Relative to 1986–2005, the frequency, intensity, and coverage of EMTEs increase by 1.13–6.84, 0.32–1.50, and 15.98%–30.68%, respectively, under 1.5°C warming; under 2.0°C warming, the increases are 1.73–12.48, 0.64–2.76, and 31.96%–50.00%, respectively. It is possible that both the intensity and coverage of future EMTEs could exceed the most severe EMTEs currently observed. Two new centers of EMTEs are projected to develop under 1.5°C warming, one in North China and the other in Southwest China. Under 2.0°C warming, a fourth EMTE center is projected to develop in Northwest China. Under 1.5 and 2.0°C warming, population exposure is projected to increase by 23.2%–39.2% and 26.6%–48%, respectively. From a regional perspective, population exposure is expected to increase most rapidly in Southwest China. A greater proportion of the population in North, Northeast, and Northwest China will be exposed to EMTEs under 2.0°C warming. The results show that a warming world will lead to increases in the intensity, frequency, and coverage of EMTEs. Warming of 2.0°C will lead to both more severe EMTEs and the exposure of more people to EMTEs. Given the probability of the increased occurrence of more severe EMTEs than in the past, it is vitally important to China that the global temperature increase is limited within 1.5°C.  相似文献   

利用TWP-ICE试验资料对比两种边界层参数化方案   总被引：1，自引：1，他引：0       下载免费PDF全文

沈新勇  黄文彦  王卫国  郭春燕 《应用气象学报》2014,25(4):385-396

利用高分辨率WRF单气柱模式,选取了两种边界层参数化方案(YSU,MYJ),对TWP-ICE(Tropical Warm Pool International Cloud Experiment)试验期间的个例进行数值模拟,比较了两种方案对边界层结构、云和降水模拟的影响。结果表明:季风活跃期,YSU方案模拟的湍流交换系数较小,湍流混合偏弱,边界层内热通量偏小,使地表热量和水汽不易向上输送,水汽含量在近地表明显偏多,而在边界层及其以上大气层具有显著的干偏差,因此该方案模拟的云中液态水和固态水含量偏低,云量偏少,降水率偏小;MYJ方案对于季风活跃期的边界层结构具有较好的模拟能力,其模拟的云和降水更为准确。季风抑制期,MYJ方案模拟的夜间边界层结构存在较大误差,这是因为该方案模拟的夜间湍流交换系数较大,湍流混合偏强,边界层内热通量偏大,模拟的位温和水汽混合比在边界层内随高度变化较小,而观测廓线在边界层内存在较大梯度。季风抑制期两种方案模拟的云和降水均比观测值偏多,方案之间的差异较小。  相似文献   

利用雷达资料对自动雨量计实时质量控制的方法研究   总被引：4，自引：1，他引：3  

王红艳  王改利  刘黎平  江源  王丹  李丰 《大气科学》2015,39(1):59-67

自动雨量计资料是对降水的直接测量,在流域面雨量计算、气候研究、气象服务等方面具有重要意义。但是,由于风力、蒸发、灌溉、校准、漏斗堵塞、机械故障、信号传输等原因往往造成其存在不同类型的系统误差和随机误差, 自动雨量计数据在定量使用前需要进行质量控制。目前,天气雷达以其高时空分辨率的优势已经成为监测降水的重要手段,本文首先采用两步校准法改善雷达估测降水,然后对雷达—雨量计对之间的差异进行统计学的分析,确定自动雨量计质量控制的一些标准,从而对雨量计进行质量控制。最后用两个降水过程对自动雨量计质量控制的结果进行了检验,结果表明:两步校准法改善了雷达估测降水的系统性偏差,并减小了雨量计站点上的相对误差;可以利用雷达估测降水实现对自动雨量计的实时质量控制,就整个数据集而言,约0.1%的数据被怀疑为误判,误判的自动雨量计主要位于雨带的边缘。但该质量控制算法同时也存在一定的局限性:在雨带的边缘或没有天气雷达覆盖的区域,以及雷达资料存在数据质量问题的情况下,往往会造成对雨量计的误判。  相似文献   

Projection of PM2.5 and Ozone Concentration Changes over the Jing-Jin-Ji Region in China          下载免费PDF全文

WU Jie  XU Ying  ZHANG Bing 《大气和海洋科学快报》2015,8(3):143-146

Based on GISS-E2-R model simulations, the changes in PM2.5 and ozone concentrations during 2016– 35 are analyzed over the Jing-Jin-Ji region under different future emissions scenarios: 2.6, 4.5, 6.0, 8.5 Representative Concentration Pathways scenarios(RCP2.6, RCP4.5, RCP6.0, and RCP8.5), compared to the baseline periods of 1851–70(pre-industrial) and 1986–2005(present day). The results show that PM2.5 increases under all emissions scenarios, with the maximum value occurring in the southeastern part of the region under most scenarios. As for ozone, its concentration is projected to increase during 2016–35 under all emissions scenarios, compared to the baseline periods. The temporal evolutions of PM2.5 and ozone show PM2.5 reaching a peak during 2020–40, while ozone will likely increase steadily in the future.  相似文献