基于GIS的新疆气温数据栅格化方法研究

以新疆99个气象台站1971-2010年年平均气温为数据源,采用多元回归结合空间插值的方法对新疆区域气温数据进行栅格化研究。建立了年平均气温与台站经纬度和海拔高度的多元回归模型,对于残差数据的插值采用了反距离权重法(IDW) 、普通克立格法 (Kriging)和样条函数法(Spline)3种目前应用广泛的空间插值方法,针对于这3种方法进行了基于MAE和RMSIE的交叉验证和对比分析,结果表明在新疆的年平均气温的GIS插值方案中,IDW方法精度总体要高于其他两种插值方法。     

中国陆地区域气象要素的空间插值

在区域农田生态系统生产力模拟模型研究中，空间插值可以提供每个计算栅格的气象要素资料。然而，在众多的气象要素空间插值方法中，并没有一种适合每一个气象要素的普适的最佳插值方法。本文以全国７２５站１９５１～１９９０年整编资料中的旬平均温度和计算得来的６７５站的月乎均光合有效辐射日总量（ＰＡＲ）为数据源，选用了距离平方反比法（ＩＤＳ）、梯度距离平方反比法（ＧＩＤＳ）和普通克立格法（ＯＫ）等３种插值方法，进行了方法选取的探讨。交叉验证结果表明：３种方法中，温度插值的平均绝对误差（ＭＡＥ）的排序为ＩＤＳ＞ＯＫ＞ＧＩＤＳ，其值分别为２．１５℃、１.９０℃和 ｌ．３２℃；在作物生长季节（４－１０月），ＭＡＥ分别 ２０℃、１．９℃和 １.２℃ ，表明ＧＩＤＳ在温度插值方面更具实用价值；对于ＰＡＲ，ＭＡＥ的排序为ＯＫ＞ＧＩＤＳ＞ＩＤＳ，其值分别为 ０．８３ＭＪ／ｍ２、０７１ＭＪ／ ｍ２和 ０．４６ＭＪ／ｍ２，说明复杂的方法并不必然具有更好的效果。对这２个气象要素的空间分布特征分析表明：温度和ＰＡＲ的经、纬向梯度和高度梯度均具有明显的季节性变化特征；温度的纬向梯度有近似正弦曲线的较强的季节变化，表现为夏季高，而冬、春季低；温度的高度梯度年     

秦岭—大巴山高分辨率气温和降水格点数据集的建立及其对区域气候的指示

本文建立了秦岭—大巴山高分辨率(～29 m×29 m)的气候格点数据集,包括逐月气温和降水、年均温和年降水、春夏秋冬气温和降水。空间插值方法采用国际上较为先进的ANUSPLIN软件内置的薄盘光滑样条函数,以经度、纬度和海拔为独立变量。空间插值结果与流行的WorldClim 2.0气候格点数据集具有一致性,但是比后者更精确、分辨率更高、细节更突出。本文揭示和证实:秦岭南麓是最冷月气温的0℃分界线。秦岭—大巴山气温具有明显的垂直地带性。6月气温直减率最大,为0.61℃/100 m;12月气温直减率最小,为0.38℃/100 m;年均气温直减率为0.51℃/100 m。夏季和秋季降水从西南向东北递减,强降水中心出现在大巴山西南坡。冬季降水从东南向西北递减。大巴山是年降水1000 mm分界线,夏季降水500mm分界线;秦岭是年降水800 mm分界线,夏季降水400 mm分界线。与大尺度大气环流对比揭示:秦岭—大巴山气温和降水空间分布主要受到东亚季风和地形因子的控制。本文进一步明确了秦岭和大巴山的气候意义:大巴山主要阻挡夏季风北上,影响降水空间分布;秦岭主要阻挡冬季风南下,影响冬季气温空间分布。本文建立的高分辨率气候格点数据集,加深了对区域气候的认识,并将有多方面的用途。     

不同时间尺度、季节的气温数据空间平稳特征及其对插值结果的影响

不同时间尺度、季节的气温数据表现出不同的空间平稳特征。为探讨分析空间平稳性对气温插值的影响规律,采用趋势线法对气温数据进行空间平稳性探索,并对比分析不同空间平稳性条件下,普通线性回归、普通克里格、回归克里格的气温插值精度及插值结果的空间分布特点。结果显示：冬季日均、月均气温与年均气温呈现空间非平稳,插值精度随时间序列的增长而提高,随着气温数据逐渐趋于稳定,精度提高的幅度逐渐下降;夏季日均、月均气温呈现空间平稳,随时间序列的增长,插值精度的提高并不显著;夏季日均气温各插值方法的插值精度普遍高于冬季日均气温。与普通克里格相比,回归克里格能有效提高空间非平稳数据的插值精度。时间序列的增长削弱了不同插值算法之间的插值精度差异和插值结果空间分布差异。     

薄板光顺样条插值与中国气候空间模拟

利用720个气象台网的长期平均气象数据拟合具有三维地理空间的气候曲面,并与1km空间分辨率的数字高程模型相结合,对气候变量的规则栅格进行插值估计。对各月平均最低温度、平均最高温度和降水量的插值结果构成了基础数字气候空间,以满足地理信息系统的数据分析需求。插值过程提供的误差统计表明插值的温度误差普遍小于0.6度,降水误差范围在8%~15%,明显优于其它插值方法。样条法利用线性模型反映地形对气候的影响,并提供了简便的误差诊断程序,具有良好的实用性。     

1900-2009 年中国均一化逐月降水数据集研制

收集、整理全国1900-2009 年110 年逐月站点历史降水量资料,采取标准正态检验(SNHT) 方法,对台站序列进行了均一性检验,并对部分明显不连续的站点序列进行了均一化调整和订正。在此基础上,分别对近百年降水距平序列和1971-2000 年气候标准值进行了网格化,形成了逐月网格化气候数据集(5°×5°,2°×2°),并采用经验正交展开(EOF) 技术方案进行了统计插补实验,形成了完整的5°×5°经纬度网格点数据集。基于不同分辨率网格数据集,建立了110 年中国降水变化序列,计算了110 年中年及季节降水量变化趋势。结果表明,中国近110 年来年降水量变化略呈下降趋势,但没有达到统计显著性水平,各个季节的情况略有差别。统计插补后对1900年以后几年的降水量略有下降,使得近百年线性趋势略上升。     

A Regional Scale Investigation of Climatological Tropical Convection and Precipitation in the Amazon Basin

This study constructs a regional scale climatology of tropical convection and precipitation from more than 15 years of monthly outgoing longwave radiation (OLR) and precipitation data on 2.5°× 2.5° latitude‐longitude grid to examine the spatial and temporal patterns and variability of convection and precipitation in the Amazon Basin. A linear regression analysis also detects if any trends exist in the two datasets. The region of study extends from 15°N to 25°S and 30° to 80°W that encompass the Amazon Basin and surrounding fringe areas for the period from January 1979 through December 1995 for the OLR data and up to 1996 for the precipitation dataset. The basin‐average mean monthly and seasonal climatology serve as a ‘baseline’ reference for comparison with the full time series of basin‐average monthly OLR and precipitation to illustrate the interannual variability and identify anomalous periods of wet and dry conditions. A linear trend analysis of OLR data found small negative values across the Amazon Basin indicating a slight increase in convective activity over the period of study. The analysis of the precipitation time series, however, shows no coincidental increase in precipitation as would be expected with an increase in convective activity. Portions of Rondônia and Mato Grosso, areas that have undergone extensive deforestation, illustrate no trend in precipitation as suggested by GCM simulation results. The only area featuring any large change in precipitation occurs in a small area in the northwestern region of South America where a large positive trend in precipitation exists.     

Climate spatial variability and data resolution in a semi-arid watershed, south-eastern Arizona

In the 10,000 km² San Pedro River watershed area in south-eastern Arizona, high-resolution spatial patterns of long-term precipitation and temperature were better reproduced by kriging climate data with elevation as external drift (KED) than by multiple linear regression on station location and elevation as judged by the spatial distribution of interpolation error. Mean errors were similar overall, and interpolation accuracy for both methods increased with increasing correlation between climate variables and elevation. Uncertainty in station locations had negligible effect on mean estimation error, although error for individual stations varied as much as 27%. Our future ability to examine spatial aspects of climate change at high spatial resolution will be severely limited by continuing closures of climate stations in this part of the United States.     

川渝地区气温随地形、经度和纬度的变化(英文)

Using the daily temperature data of 95 meteorological stations from Si-chuan-Chongqing Region and its surrounding areas, this paper adopted these methods (e.g., linear regression, trend coefficient, geographical statistics, gray relational analysis and spatial analysis functions of GIS) to analyze the relations of temperature variability with topography, latitude and longitude. Moreover, the rank of gray correlation between temperature variability and elevation, longitude, latitude, topographic position and surface roughness also was measured. These results indicated: (1) The elevation affected temperature variability most obviously, followed by latitude, and longitude. The slope of the linear regression between temperature change rate and elevation, latitude and longitude was 0.4142, 0.0293 and -0.3270, respectively. (2) The rank of gray correlation between temperature change rate and geographic factors was elevation > latitude > surface roughness > topographic position > longitude. The gray correla-tion degree between temperature change rate and elevation was 0.865, followed by latitude with 0.796, and longitude with 0.671. (3) The rate of temperature change enhanced with the increase of elevation. Especially, the warming trend was significant in the plateau and mountain areas of western Sichuan, and mountain and valley areas of southwestern Sichuan (with the warming rate of 0.74℃/10a during the 1990s). However, there was a weak warming trend in Sichuan Basin and its surrounding low mountain and hilly areas. (4) The effects of latitude on temperature change rate presented the specific regulation, which the warming rate of low-latitude areas was more significant than that of high-latitude areas. However, they were consistent with the regulation that the increasing of low temperature controlled most of the warming trend, due to the effects of terrain and elevation on annual mean temperature. (5) Ba-sically, temperature variability along longitude direction resulted from the regular change of elevation along longitude. It was suggested that, in Sichuan-Chongqing Region, special features of temperature variability largely depended on the terrain complexity (e.g., undulations, mutations and roughness). The elevation level controlled only high or low annual mean temperature and the range of temperature change rate in the macro sense.     

中国高分辨率温度和降水模拟数据的验证

PRISM模型是一种基于地理特征和回归统计方法生成气候图的模型。基于中国及其周边国家地区2450多个气象台站观测数据,以PRISM模型模拟生成了中国2.5′×2.5′(≈4～5km)逐月温度和降水数据。利用独立于模拟数据的中国生态系统研究网络18个野外观测站的长年气候观测数据,检验了PRISM模型的模拟结果,表明PRISM模型较好地模拟了我国温度和降水的空间分布及季节变化,除了在高山和亚热带地区由于地表覆盖和局部地形的差异影响模拟结果,其模拟值与实测值之间的趋势线同1∶1线基本一致,具有显著相关关系,其中降水效果略差     

EVALUATION OF GRIDDED PRECIPITATION FOR NORWAY USING GLACIER MASS‐BALANCE MEASUREMENTS

The service seNorge ( http://senorge.no ) provides gridded temperature and precipitation for mainland Norway. The products are provided as interpolated station measurements on a 1 × 1 km grid. Precipitation gauges are predominantly located at lower elevations such as coastal areas and valleys. Therefore, there are large uncertainties in extrapolating precipitation data to higher altitudes, both due to sparsity of observations as well as the large spatial variability of precipitation in mountainous regions. Using gridded temperature and precipitation data from seNorge, surface mass balance was modeled for five Norwegian glaciers of different size and climate conditions. The model accounts for melting of snow and ice by applying a degree‐day approach and considers refreezing assuming a snow depth depended storage. Calculated values are compared to point measurements of glacier winter mass balance. On average for each glacier, modeled and measured surface mass‐balance evolutions agree well, but results at individual stake locations show large variability. Two types of problems were identified: first, grid data were not able to capture spatial mass balance variability at smaller glaciers. Second, a significant increase in the bias between model and observations with altitude for one glacier suggested that orographic enhancement of precipitation was not appropriately captured by the gridded interpolation.     

基于GIS的定位观测数据空间化

属性数据空间化是当前GIS领域的前沿问题之一。在对中国624个气象站多年平均气温数据空间化过程中,通过使用30秒分辨率的数字高程数据,把气温分解为受经纬度、海拔高度影响的规律性成分和受其它因素影响的非规律性成分两部分,并分别用多元回归和反距离权重内插方法对二者实施空间化,最后将空间化结果进行合成得到基于栅格的中国多年平均气温分布数据。该数据既能反映气温在空间上的宏观变化,又能反映气温在局部地区的微观变化。该方法可供其它类型观测数据空间化、特别是在观测站点稀疏的情况下参考和借鉴。     

Downscaling climate-model output in mountainous terrain using local topographic lapse rates for hydrologic modeling of climate-change impacts

One of the challenges in using general circulation model (GCM) output is the need to downscale beyond the model’s coarse spatial grid for use in hydrologic modeling of climate-change impacts. In mountainous terrain, using elevation as a primary control on temperature and precipitation at the local scale provides the potential for topographic variables to be used to adjust climate-model output. Here, local topographic lapse rates (LTLR) were estimated from gridded climate data for the Pacific Northwest of the United States and used to downscale GCM output. Skill scores were calculated for the LTLR-downscaled climate-model output relative to an existing set of model output downscaled using the established statistical downscaling technique of localized constructed analogs (LOCA). The results indicate that the LTLR method performs well in the mountainous study region relative to the LOCA method. LTLR downscaling offers a promising method for downscaling climate-model output in regions in which elevation strongly controls climate, particularly for studying impacts of future climate change on water resources.     

近50 a新疆气温精细化时空变化分析

利用新疆93个气象站1961-2010年的逐月平均气温资料,使用线性趋势分析、Mann-Kendall检测以及基于ArcGIS的混合插值法对春、夏、秋、冬四季和年平均气温的变化趋势、突变特征以及各气温要素多年平均值和突变前后变化量的空间分布进行了分析。结果表明：（1）新疆春、夏、秋、冬四季和年平均气温的空间分布总体呈现“南疆高,北疆低;平原和盆地高,山区低”的格局。（2）在全球变暖背景下,1961-2010年新疆春、夏、秋、冬四季和年平均气温分别以0.24 ℃/10 a、0.21 ℃/10 a、0.39 ℃/10 a、0.49 ℃/10 a和0.33℃/10 a的倾向率呈显著的上升趋势,并分别于2004年、1997年、1995年、1985年和1994年发生了突变性的上升,突变后较突变前,各季和年平均气温分别升高了1.5 ℃、0.8 ℃、1.2 ℃、1.6 ℃和1.0 ℃,但气温上升幅度具有明显的区域性差异,其空间分布总体呈现“北疆大,南疆小”的格局。     

Terrain analysis for active tectonic zone characterization: a new application for MODIS night LST (MYD11C3) data set

A new context for active tectonic zone recognition is proposed on the basis of the exporting energy of the terrain features at continental scale. Toward this end, elevation, latitude, and longitude decorrelation stretch of multi-temporal moderate resolution imaging spectroradiometer (MODIS) monthly average land surface temperature (LST) imagery (MYD11C3) is applied in a study area extending from Red Sea to Indian Ocean and from Persian Gulf to Black Sea and Caspian Sea. Multiple linear regression analysis of principal components images (principal components analysis (PCAs)) quantified the variance explained by elevation, latitude, and longitude. Selective variance reduction reconstructed the multi-temporal LST imagery from the residual images and selected PCAs by taking into account the portion of variance that is not related to elevation, latitude, and longitude. The reconstructed imagery presents the magnitude the standardized LST value per pixel deviates from the elevation, latitude, and longitude predicted one, whereas a positive LST anomaly is defined as a region that presents positive reconstructed LST value throughout the year. Clustering of the reconstructed standardized imagery mapped a great positive LST anomaly of tectonic origin that occupies the greatest in elevation and most massive areas, forming three regions: (a) the Himalayan Belt along the Pakistan, Afghanistan borders, and the Eastern Alpine zone (Makhran Ranges and Zagros Ranges), (b) the coastal zone (along the Red Sea) of the Arabian Shield, and (c) the Oman Mountains Province along the Persian Gulf. The method will allow the classification of terrain objects (e.g. mountains, basins) on the basis of both the exporting energy (reconstructed LST) and geomorphometry.     

The use of high-resolution gridded climate data in the development of chironomid-based inference models from remote areas

The development of chironomid-based air temperature inference models in high latitude regions often relies on limited spatial coverage of meteorological data and/or on punctual measurements of water temperature at the time of sampling. The use of simple linear regression to relate air temperature and latitude was until recently the best method to characterize the air temperature gradient along a latitudinal gradient. However, recent studies have used high-resolution gridded climate data to develop new chironomid-based air temperature inference models. This innovative approach has, however, never been further analyzed to test its reliability. This study presents a method using ArcGIS^® to extract air temperatures from a high-resolution global gridded climate data set (New et al. 2002) and to incorporate these new data in a variety of chironomid-based air temperature inference models to test their performance. Results suggest that this method is reliable and produces better estimates of air temperature and will be helpful in the development of further quantitative air temperature inference models in remote areas.     

新疆气候时空变化特征及其趋势(英文)

Temperature and precipitation time series datasets from 1961 to 2005 at 65 meteorological stations were used to reveal the spatial and temporal trends of climate change in Xinjiang, China. Annual and seasonal mean air temperature and total precipitation were analyzed using Mann-Kendall (MK) test, inverse distance weighted (IDW) interpolation, and R/S methods. The results indicate that: (1) both temperature and precipitation increased in the past 45 years, but the increase in temperature is more obvious than that of precipitation; (2) for temperature increase, the higher the latitude and the higher the elevation the faster the increase, though the latitude has greater influence on the increase. Northern Xinjiang shows a faster warming than southern Xinjiang, especially in summer; (3) increase of precipitation occurs mainly in winter in northern Xinjiang and in summer in southern Xinjiang. Ili, which has the most precipitation in Xinjiang, shows a weak increase of precipitation; (4) although both temperature and precipitation increased in general, the increase is different inside Xinjiang; (5) Hurst index (H) analysis indicates that climate change will continue the current trends.     

三个全球气候模式对中国气温季节变化模拟能力的空间差异特征分析

针对第五次国际耦合模式比较计划（CMIP5）中3个全球气候模式对中国气温季节变化模拟能力的空间差异特征进行具体分析。结果表明：BCC-CSM1.1（m）模式和GFDL-CM3模式能够再现中国气温的季节性变化,在中国东部地区模拟能力较强,平均绝对误差和均方根误差均较小,在中国西部地区模拟能力较弱,平均绝对误差和均方根误差较大。与BCC-CSM1.1（m）和GFDL-CM3模式相比,HADGEM2-ES模式再现中国地区气温季节变化的能力最弱,平均绝对误差和均方根误差在西部部分地区、内蒙古地区和东北地区较大,在华南地区南部较小。在相同模式下,日平均气温模拟效果最好,其次是日最低气温,日最高气温模拟效果最差。纬度、经度、海拔和坡度对气候模式模拟效果的影响存在模式间的差异,而坡向和地形遮蔽度对模式的模拟效果无明显影响。     

SRTM resample with short distance‐low nugget kriging

The shuttle radar topography mission (SRTM), was flow on the space shuttle Endeavour in February 2000, with the objective of acquiring a digital elevation model of all land between 60° north latitude and 56° south latitude, using interferometric synthetic aperture radar (InSAR) techniques. The SRTM data are distributed at horizontal resolution of 1 arc‐second (～30 m) for areas within the USA and at 3 arc‐second (～90 m) resolution for the rest of the world. A resolution of 90 m can be considered suitable for the small or medium‐scale analysis, but it is too coarse for more detailed purposes. One alternative is to interpolate the SRTM data at a finer resolution; it will not increase the level of detail of the original digital elevation model (DEM), but it will lead to a surface where there is the coherence of angular properties (i.e. slope, aspect) between neighbouring pixels, which is an important characteristic when dealing with terrain analysis. This work intents to show how the proper adjustment of variogram and kriging parameters, namely the nugget effect and the maximum distance within which values are used in interpolation, can be set to achieve quality results on resampling SRTM data from 3” to 1”. We present for a test area in western USA, which includes different adjustment schemes (changes in nugget effect value and in the interpolation radius) and comparisons with the original 1” model of the area, with the national elevation dataset (NED) DEMs, and with other interpolation methods (splines and inverse distance weighted (IDW)). The basic concepts for using kriging to resample terrain data are: (i) working only with the immediate neighbourhood of the predicted point, due to the high spatial correlation of the topographic surface and omnidirectional behaviour of variogram in short distances; (ii) adding a very small random variation to the coordinates of the points prior to interpolation, to avoid punctual artifacts generated by predicted points with the same location than original data points and; (iii) using a small value of nugget effect, to avoid smoothing that can obliterate terrain features. Drainages derived from the surfaces interpolated by kriging and by splines have a good agreement with streams derived from the 1” NED, with correct identification of watersheds, even though a few differences occur in the positions of some rivers in flat areas. Although the 1” surfaces resampled by kriging and splines are very similar, we consider the results produced by kriging as superior, since the spline‐interpolated surface still presented some noise and linear artifacts, which were removed by kriging.     

近15a新疆不同类型植被NDVI时空动态变化及对气候变化的响应

为了研究新疆不同类型植被对气候变化的响应,以地带性划分的植被类型作为研究对象,1998-2012年为时间尺度,利用GIS的空间分析方法结合数学统计方法,分析了新疆各地带植被覆盖变化的时空分布特征;并采用"多元回归+残差插值"的方法,模拟了气温和降水量的空间分布;利用SPOT VGT/NDVI数据以及气候数据(气温和降水量数据),分析了5个不同地带植被的动态变化、年际变化和生长季内各月变化及其对气候变化的响应。结果表明:(1)新疆各地带植被覆盖度存在着显著差异,其中,温带北部草原地带高植被区和浓密植被区的范围较广,植被覆盖度较高,而高寒荒漠地带的极低植被区占该地带面积的一半以上,且植被覆盖度最低。(2)新疆各地带植被覆盖在近15 a间呈波动增加的趋势,5个地带的植被覆盖均有所改善,其中,高寒荒漠地带和暖温带半灌木、灌木地带的植被覆盖改善较为明显,其余3个地带均有少部分地区出现轻微改善现象。(3)温带半灌木、矮乔木荒漠地带,暖温带半灌木、灌木荒漠地带和温带半灌木、灌木荒漠地带4~10月的平均气温呈上升趋势,而温带北部草原地带、高寒荒漠地带对应的平均气温则出现下降趋势。5个地带的降水量在该时段内均表现为下降趋势。(4)基于年际尺度,新疆各地带植被NDVI与气温、降水量的相关性均不显著;基于月尺度,各地带植被NDVI受降水量的影响比气温大。同时,仅有暖温带半灌木、灌木荒漠地带植被NDVI与气温存在1个月的滞后性,其余4个地带对气温和降水均不存在滞后性。