热带太平洋气候变率的三类模态及与ENSO强度变化的关系

基于Kaplan等重建的1856—2001年全球海表水温距平(SSTA)资料，用小波变换分析了热带太平洋SSTA的气候变率，对热带太平洋SSTA分别进行2—8、8—30和30—100a带通滤波，然后进行EOF分解。结果发现，ENSO模态具有5a左右的年际变化和15a左右的年代际变化2种显著周期，当二者位相相同时，ENSO事件加强，当二者位相相反时，ENSO事件减弱，当年际变化不明显时，显著的年代际变化也可单独导致ENSO事件；热带太平洋SSTA气候态变率以西太平洋暖池和赤道两侧的热带中东太平洋明显海温同号异常为主要特征，具60a左右的周期，其相位变化与气候跃变及El Nifio事件的类型有密切联系；长期增温倾向加大了El Nifio事件的振幅。文章最后指出，ENSO事件强度变化是由年际、年代际和气候态等3类模态变率共同作用的结果，在ENSO预报模式中考虑并引入年代际和气候态变化对ENSO循环的影响，是提高ENSO预测水平的有效途径之一。     

陆源输入营养盐对赤潮形成的影响

有害赤潮是国际社会共同关注的重大海洋环境问题和生态灾害。自20世纪70年代以来,我国有记录的赤潮发生了500多次,发生次数以每10年增加3倍的速度上升[1~3]。赤潮频发不仅会破坏生态平衡,危害资源环境,而且赤潮毒素还会通过食物链导致人体中毒,危害人体健康,因此赤潮的预防和治     

Spatial and temporal groundwater dynamics in extreme arid basins

To accurately obtain the spatial distribution characteristics of groundwater level in an extremely arid zone and its dynamic change patterns under the influence of human activities, based on the data of 55 groundwater observation wells in the middle and lower reaches of the Kriya River, spatial interpolation of regional groundwater level data were performed using the inverse distance weight, spline function, trend surface, and the ordinary kriging methods. The optimal interpolation method was selected by its accuracy to spatially interpolate the groundwater level data in the study area from 2019 to 2021. The results show that: (1) the ordinary kriging method has the highest interpolation accuracy (MAE = 7.1393, MRE = 0.0058, RMSE = 9.4314) and reflects the spatial and temporal variability and distribution characteristics of groundwater levels with great accuracy. (2)The relationship between surface water–groundwater recharge and discharge in different areas of the river channel in the desert section varies depending on geological structure, surface water seepage, and other elements. (3) Groundwater in the Taklamakan Desert has little effect on groundwater recharge in the Dariyabui Oasis, and changes in groundwater dynamics in the oasis are predominantly influenced by surface runoff. (4) Monthly changes in groundwater levels in the Yutian Oasis are continuous, with ‘V’ shaped fluctuations, a declining trend in the southern part, no significant change in the central part, and a slight increase in the northern part. These results contribute to the sustainable management of water resources in the Kriya River Basin, provide a basis for groundwater prediction, and offer a reference for studies of other, similar extreme desert area basins.     

Factors affecting the sediment concentration in runoff from a slope during the spring thawing period

Sediment concentration (S) is vital in soil erosion models. However, research on estimating S at different positions on slopes in the spring thaw period is difficult. Thus, in this research, four flow discharges, two slope gradients, and four initial thawing depths were used in combination with Rare Earth Elements (REEs) tracing techniques to investigate the effects of hydraulic parameters at different locations of freeze–thaw rill flows on S. The results show that the S on the freeze–thaw slope gradually increases from the first section to the third section of the slope, with an increase of 43.99% from the first slope section to the third slope section. The flow velocity is the most critical factor to affect the S (R² > 0.7). The prediction equation of S on the entire slope under freeze–thaw conditions was established based on the flow turbulence intensity and relative gravity (R² = 0.769). This study examined the S and hydraulic parameters of the freeze–thaw rill flow, which provided a reference for further research on the soil erosion model during the spring thawing period.     

Classifying historical remotely sensed imagery using a tempo-spatial feature evolution (T-SFE) model

Large and growing archives of orbital imagery of the earth’s surface collected over the past 40 years provide an important resource for documenting past and current land cover and environmental changes. However uses of these data are limited by the lack of coincident ground information with which either to establish discrete land cover classes or to assess the accuracy of their identification. Herein is proposed an easy-to-use model, the Tempo-Spatial Feature Evolution (T-SFE) model, designed to improve land cover classification using historical remotely sensed data and ground cover maps obtained at later times. This model intersects (1) a map of spectral classes (S-classes) of an initial time derived from the standard unsupervised ISODATA classifier with (2) a reference map of ground cover types (G-types) of a subsequent time to generate (3) a target map of overlaid patches of S-classes and G-types. This model employs the rules of Count Majority Evaluation, and Subtotal Area Evaluation that are formulated on the basis of spatial feature evolution over time to quantify spatial evolutions between the S-classes and G-types on the target map. This model then applies these quantities to assign G-types to S-classes to classify the historical images. The model is illustrated with the classification of grassland vegetation types for a basin in Inner Mongolia using 1985 Landsat TM data and 2004 vegetation map. The classification accuracy was assessed through two tests: a small set of ground sampling data in 1985, and an extracted vegetation map from the national vegetation cover data (NVCD) over the study area in 1988. Our results show that a 1985 image classification was achieved using this method with an overall accuracy of 80.6%. However, the classification accuracy depends on a proper calibration of several parameters used in the model.     

浅谈察右中旗库伦苏木防雷工程勘测和设计方案

有资料表明：全世界每天发生800万次雷电,平均每秒近100次．每个闪电的强度高达10亿伏特．功率可达10万千瓦．相当于一个小型核电站的输出功率;全球每年因雷击造成的损失约10～50亿美元,我国是雷害比较严重的国家．每年因雷击造成的人员伤亡700～1000人。财产损失50～100亿人民币。     

An Adaptive Method of High Accuracy Surface Modeling and Its Application to Simulating Elevation Surfaces

An adaptive method is employed to speed up computation of high accuracy surface modeling (HASM), for which an error indicator and an error estimator are developed. Root mean‐square error (RMSE) is used as the error estimator that is formulated as a function of gully density and grid cell size. The error indicator is developed on the basis of error surfaces for different spatial resolutions, which are interpolated in terms of the absolute errors calculated at sampled points while paying attention to the landform characteristics. The error surfaces indicate the magnitude and distribution of errors in each step of adaptive refinement and make spatial changes to the errors in the simulation process visualized. The adaptive method of high accuracy surface modeling (HASM‐AM) is applied to simulating elevation surface of the Dong‐Zhi tableland with 27.24 million pixels at a spatial resolution of 10 m × 10 m. Test results show that HASM‐AM has greatly speeded up computation by avoiding unnecessary calculations and saving memory. In addition, HASM‐AM improves simulation accuracy.     

鄂尔多斯地区2007年冬季异常气候影响的思考

通过对鄂尔多斯地区2007年冬季异常气候及产生的灾害性天气事件进行了调查,结合IPCC公布的最新数据及专家研究成果,提出了鄂尔多斯地区应对异常气候造成的灾害性天气事件的一些措施。     

Periodicities Near 160 Minutes in Flare Occurrence

The 160.01-min periodicity was originally found from line-of-sight velocities of the photosphere, and Kotov and Tsap reported a detection of the same periodicity in flare occurrence times. Intrigued by this, I analyze occurrence times of flares of cycles 19–23 to investigate periodicities in the neighborhood of 160 min, cycle by cycle. The 160.01-min periodicity is not detected from any cycle. However, a 160.69 min periodicity is detected in the spectrum for cycle 19, and a 160.32-min periodicity is detected in the power spectrum for major flares of cycle 21. The 160.32-min periodicity did not influence the occurrence rate of flares with X-ray classes below M3.0. Among major flares, the amplitude of modulation increases with increasing X-ray class.     

湖泊水质遥感研究进展

详述了湖泊遥感水质最新发展动态,如遥感水质模型的数学方法、与水质指标最敏感的波段以及TM、SPOT、MODIS、MERIS、AVHRR、CASI等传感器的适用情况,并分析了可能导致湖泊水质遥感模型误差的原因和解决办法。湖泊各项水质组分与光谱之间相互影响可认为是一种非常复杂的非线性关系,最适合用神经网络这样的黑箱模型来模拟。应当研究和选取敏感波段,用高光谱逐段分析与各种水质指标相关最密切的波段。湖泊水质遥感最终走向实用化必将其与水生态问题结合起来,作为一种监测手段,在水中藻类的时空分布、流域营养物质输送模型和湖泊水域水质模型等问题中得到广泛应用。我国学者使用超光谱数据源获得更为精确的监测成果还比较少,由于我国卫星可以用来进行水质遥感的波段比较宽,应当在新一代的资源环境卫星上加入更适合水质遥感的波段。