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331.
利用雷达回波与GIS技术反演面雨量研究 总被引:5,自引:0,他引:5
自动气象站可以直接测量单点或较小范围的降水量,测量精度较高,但自动气象站的分布密度不够,往往漏掉强降水、暴雨中心。雷达能实时探测云和降水结构及系统发生、发展演变情况,能迅速提供一定区域的实时降水情况,但雷达测量误差较大,测定局地降水量精度不高,因此,将自动气象站与雷达进行点面结合,采用一定的数学方法和GIS技术,可以得到能够代表某特定区域平均降水情况的面雨量。以深圳市行政区域面雨量反演为例,建立区域内所有测站的6 min累积降雨资料与雷达回波数据之间的回归关系,借助GIS技术和包括对经度、纬度、海拔高度3个因子的地理订正,构建雷达图上特定行政区域的面雨量计算模型,并对格点拟合雨量进行空间分辨率的精细化反演,得到雷达图上的特定行政区域的面雨量图。 相似文献
332.
333.
A nested regional climate model has been experimentally used in the seasonal prediction at the China National Climate Center (NCC) since 2001. The NCC/IAP (Institute of Atmospheric Physics) T63 coupled GCM (CGCM) provides the boundary and initial conditions for driving the regional climate model (RegCM NCC). The latter has a 60-km horizontal resolution and improved physical parameterization schemes including the mass flux cumulus parameterization scheme, the turbulent kinetic energy closure scheme (TKE) and an improved land process model (LPM). The large-scale terrain features such as the Tibetan Plateau are included in the larger domain to produce the topographic forcing on the rain-producing systems. A sensitivity study of the East Asian climate with regard to the above physical processes has been presented in the first part of the present paper. This is the second part, as a continuation of Part I. In order to verify the performance of the nested regional climate model, a ten-year simulation driven by NCEP reanalysis datasets has been made to explore the performance of the East Asian climate simulation and to identify the model’s systematic errors. At the same time, comparative simulation experiments for 5 years between the RegCM2 and RegCM NCC have been done to further understand their differences in simulation performance. Also, a ten-year hindcast (1991–2000) for summer (June–August), the rainy season in China, has been undertaken. The preliminary results have shown that the RegCM NCC is capable of predicting the major seasonal rain belts. The best predicted regions with high anomaly correlation coefficient (ACC) are located in the eastern part of West China, in Northeast China and in North China, where the CGCM has maximum prediction skill as well. This fact may reflect the importance of the largescale forcing. One significant improvement of the prediction derived from RegCM NCC is the increase of ACC in the Yangtze River valley where the CGCM has a very low, even a negative, ACC. The reason behind this improvement is likely to be related to the more realistic representation of the large-scale terrain features of the Tibetan Plateau. Presumably, many rain-producing systems may be generated over or near the Tibetan Plateau and may then move eastward along the Yangtze River basin steered by upper-level westerly airflow, thus leading to enhancement of rainfalls in the mid and lower basins of the Yangtze River. The real-time experimental predictions for summer in 2001, 2002, 2003 and 2004 by using this nested RegCM NCC were made. The results are basically reasonable compared with the observations. 相似文献
334.
V. Čermák J. Šafanda L. Bodri M. Yamano E. Gordeev 《Studia Geophysica et Geodaetica》2006,50(4):675-695
To reconstruct the recent climate history in Kamchatka, a series of repeated precise temperature logs were performed in a
number of boreholes located in a broad east-west strip (between 52 and 54°N) in the central part of Kamchatka west of Petropavlovsk-Kamchatski.
Within three years more than 30 temperature logs were performed in 10 holes (one up to six logs per hole) to the depth of
up to 400 metres. Measured temperature gradients varied in a broad interval 0 to 60 mK/m and in some holes a sizeable variation
in the subsurface temperatures due to advective heat transport by underground water was observed. Measured data were compared
with older temperature profiles obtained in the early eighties by Sugrobov and Yanovsky (1993). Even when older data are of
poorer precision (accuracy of about 0.1 K), they presented valuable information of the subsurface temperature conditions existing
20–25 years ago. Borehole observations and the inverted ground surface temperature histories (GSTHs) used for the paleoclimate
reconstruction were complemented with a detailed survey of meteorological data. Namely, the long-term surface air temperature
(SAT) and precipitation records from Petropavlovsk station (in operation since 1890) were used together with similar data
from a number of local subsidiary meteo-stations operating in Central Kamchatka since 1950. Regardless of extreme complexity
of the local meteorological/climate conditions, diversity of borehole sites and calibration of measuring devices used during
the whole campaign, the results of the climate reconstruction supported a general warming of about 1 K characteristic for
the 20th century, which followed an inexpressive cooler period typical for the most of the 19th century. In the last three
to four decades the warming rate has been locally increasing up to 0.02 K/year. It was also shown that the snow cover played
a dominant role in the penetration of the climate “signal” to depth and could considerably smooth down the subsurface response
to the changes occurred on the surface. 相似文献
335.
Alix Lombard Anny Cazenave Pierre Yves Le Traon Stephanie Guinehut Cécile Cabanes 《Ocean Dynamics》2006,56(5-6):445-451
In this paper, we first discuss the controversial result of the work by Cabanes et al. (Science 294:840–842, 2001), who suggested that the rate of past century sea level rise may have been overestimated, considering the limited and heterogeneous
location of historical tide gauges and the high regional variability of thermal expansion which was supposed to dominate the
observed sea level. If correct, this conclusion would have solved the problem raised by the IPCC third assessment report [Church
et al, Cambridge University Press, Cambridge, pp 881, 2001], namely, the factor two difference between the 20th century observed sea level rise and the computed climatic contributions.
However, recent investigations based on new ocean temperature data sets indicate that thermal expansion only explains part
(about 0.4 mm/year) of the 1.8 mm/year observed sea level rise of the past few decades. In fact, the Cabanes et al.’s conclusion
was incorrect due to a contamination of abnormally high ocean temperature data in the Gulf Stream area that led to an overestimate
of thermal expansion in this region. In this paper, we also estimate thermal expansion over the last decade (1993–2003), using
a new ocean temperature and salinity database. We compare our result with three other estimates, two being based on global
gridded data sets, and one based on an approach similar to that developed here. It is found that the mean rate of thermosteric
sea level rise over the past decade is 1.5±0.3 mm/year, i.e. 50% of the observed 3 mm/year by satellite altimetry. For both
time spans, past few decades and last decade, a contribution of 1.4 mm/year is not explained by thermal expansion, thus needs
to be of water mass origin. Direct estimates of land ice melt for the recent years account for about 1 mm/year sea level rise.
Thus, at least for the last decade, we have moved closer to explaining the observed rate of sea level rise than the IPCC third
assessment report. 相似文献
336.
337.
川青地块在地貌上为川西高原,亦是青藏高原东北边缘最重要的构造单元。新的GPS监测资料表明,在欧亚框架内,川青地块及其邻近的龙门山带和华南地块西缘的地壳运动水平速度,具有自西向东由25.66mm/a递变下降到6.99mm/a的总趋势。速度矢量表现出顺时针涡旋转动。川青地块内具有局部应变积累的非均一的区域剪切。横切鲜水河断裂带中段新的GPS量结果揭示,两侧地块间的平均左旋滑动速率约8mm/a;由于局部应变积累,断裂系南西侧的主断裂的移动速率为9.3mm/a,其间为拉分盆地和小的横向伸展断裂。鲜水河断裂系的左旋断裂滑动作用,调节了川青地块与/11滇地块之间的相对运动。 相似文献
338.
339.
川青地块在地貌上为川西高原,亦是青藏高原东北边缘最重要的构造单元。新的GPS监测资料表明,在欧亚框架内,川青地块及其邻近的龙门山带和华南地块西缘的地壳运动水平速度,具有自西向东由25.66mm/a递变下降到6.99mm/a的总趋势。速度矢量表现出顺时针涡旋转动。川青地块内具有局部应变积累的非均一的区域剪切。横切鲜水河断裂带中段新的GPS测量结果揭示,两侧地块间的平均左旋滑动速率约8mm/a;由于局部应变积累,断裂系南西侧的主断裂的移动速率为9.3mm/a,其间为拉分盆地和小的横向伸展断裂。鲜水河断裂系的左旋断裂滑动作用,调节了川青地块与川滇地块之间的相对运动。 相似文献
340.
珠江口盆地沉降史定量模拟和分析 总被引:3,自引:0,他引:3
运用Petrosys盆地模拟系统,定量和动态地模拟了珠江口盆地三个主要坳陷的沉降过程,论述了沉降速率的变化与生储盖发育之间的关联,认为珠江口盆地构造沉降史具有幕式、多阶段变化的特征。盆地第一幕和第二幕沉降是盆地发育的主要时期,奠定了盆地的构造格架,形成了盆地主要的沉积地层和油气资源。第三幕沉降为盆地的改造和完成阶段,是盆地区域盖层发育的主要时期。 相似文献