遥感水文应用中的尺度问题

遥感技术在水文科学中的广泛应用，极大地拓宽了其研究的领域和范围，增加了其研究的深度。但同时也应该看到，遥感信息的空间分辨率和时间分辨率，以及水文科学自身尺度问题的复杂性，一方面对遥感水文的应用产生困难和问题，限制了水文遥感的应用；另一方面又对水文尺度问题提供了新的技术手段，为遥感水文应用增添了新的亮点。从水文机理与空间尺度、遥感信息的空间分辨率、水文参数的空间延拓，以及遥感技术与水文科学的发展等 4个方面探讨了遥感水文的空间尺度问题；从瞬时遥感信息的时间拓展和遥感信息的时间分辨率 2个方面讨论了遥感水文的时间尺度问题。     

河南及邻区中等地震前地震释放应变能速率B值时空演化

对河南及邻区中等地震前地震释放应变能速率B值进行时空扫描，通过对1970年至今所有ML≥4．7级地震前B值的时空演化的对比分析得出以下结论：中等地震前B值出现高值异常，且在发震前一年内结束高值，且绝大多数地震发生在B值高异常区内。     

Inferring the location of catchment characteristic soil moisture monitoring sites. Covariance structures in the temporal domain

Information shortage is a fundamental constraint in catchment hydrology that severely affects the possibilities for secure inference of the generic hydrologic landscape, as well as for secure validation of physically deduced distributed models. The introduction of databases with high enough spatiotemporal resolution to properly reflect generic hydrological catchment characteristics may therefore be considered as an inferential breakthrough. The work presented here is part of a project where observations from such an Australian catchment (the Tarrawarra) are utilised to estimate the discrepancy for individual soil moisture monitoring sites in reflecting generic catchment characteristics. With low enough discrepancy, observation sites may be considered as catchment characteristic soil moisture monitoring (CASMM) sites, thus capturing unbiased catchment characteristics and being well suited to represent the catchment in a monitoring effort. In this particular study, covariance structures in the temporal domain are inferred in order to enable subsequent enquiries regarding CASMM discrepancies. This is accomplished with ARMAX filters applied to the conditional auto- and cross-covariance structures that connect observations of soil moisture to the temporal variation of meteorology. The results suggest that weekly observations of Tarrawarra soil moisture are quite consistent realisations of first order auto-regressive processes, which means that the present state of soil moisture is generally acquired through the past week. With auto-correlative effects filtered out, cross-correlative meteorological effects on Tarrawarra soil moisture are identified and generally represented by the present week's accumulation of rainfall, the present week's accumulation of global radiation, and the previous week's maximum wind speed. After successive filtering of conditional cross-correlative effects, residual time-series observations may be considered as temporally independent, and therefore are well suited for subsequent inferences regarding covariance structures in the spatial domain. Since the exclusion of auto-correlative effects is necessary for unambiguous model interpretation, the estimated cross-correlative parameters should reflect the true nature of underlying physical processes.     

Combined discrete and continuous gravity observations at Mount Etna

Systematic investigation of discrete gravity measurements has continued at Mount Etna since 1986. The network now covers an area of 400 km² with about 70 stations 0.5–3 km apart. Mass redistributions occurring at depths ranging between about 8 km below sea level and a few hundred metres below the surface (magma level changes within the shallower parts of the feeding conduits) have been identified from these data. Conventional (discrete) microgravity monitoring on a network of stations furnishes only instantaneous states of the mass distribution at continuously active systems. In order to obtain information on the rate at which the volcanic processes (and thus mass transfers) occur, three stations for continuously recording gravity where installed on Mount Etna in 1998. A 16-month long sequence from one of the continuously running stations (PDN, located 2 km from the active northeast crater at the summit of Etna volcano) is presented. After removing the effects of Earth Tide and tilt, the correlation of the residual gravity sequence with simultaneous recordings of meteorological parameters acquired at the same station was analysed. Once the meteorological effects have also been removed, continuous gravity changes are within 10 μGal of gravity changes measured using conventional microgravity observations at sites very close to the continuous station. This example shows how discrete and continuous gravity observations can be used together at active volcanoes to get a fuller and more accurate picture of the spatial and temporal characteristics of volcanic processes.     

The Distribution and Seasonal Variation of Dissolved Trace Metals in Florida Bay and Adjacent Waters

Florida Bay is a shallow carbonate estuary in South Florida. It receives fresh waters from the Everglades that contribute a number of metals to the Bay. The Bay is the largest estuary in Florida with nearly pristine conditions. In this paper we report the first extensive studies of trace metals in the Bay. The seasonal distributions of trace metals (Sc, V, Cr, Co, Cu, Fe, Pb, Mn, Ni and Al) were determined on surface waters in Florida Bay and adjacent waters. The measurements in the Bay were made from May 2000 to May 2001, and the adjacent waters were sampled in September 2000 and May 2002. Most of the dissolved trace metals exhibited their maximum concentrations in summer, except Al and Pb that did not show any seasonal variability. The seasonal variations of the metals are related to the influx of fresh water from rainfall. The lowest concentrations are found during the dry season in the winter and the highest during the wet season in the summer. Several metals (V, Mn, Al, Sc, Fe, Co, Ni and Cr) exhibited their highest concentrations in the western zone of the Bay. These waters from agricultural areas are influenced by Gulf of Mexico waters, which carry metals coming from Barron, Broad and Shark rivers into the Bay. The Shark River always exhibited high concentrations of V, Mn, Al, Sc, Co and Cr. Other possible influences in the western and north-central zone of the Bay are from Flamingo Center, the creeks of Taylor Slough and the mangrove fringe of the Everglades. High concentrations of Al, Co, Ni, Cr, Cu, Fe, and Pb were detected in the eastern zone. The high values found in the northeast are influenced by Taylor Slough runoff and in the southeast by Key Largo, Tavernier Marina and the drainage from the main highway (US1) on Tavernier Key. The minimum concentrations for most of the metals were found in areas near the Key channels that exchange waters between Florida Bay and the Atlantic Ocean (Gulf Stream). The adjacent waters in the Atlantic side including the Gulf Stream waters showed very low concentrations for all the metals studied except for V. In the Bay correlations of V were found: (1) V with salinity and Al and (2) Sc with Si. Most of the other metals did not show any strong correlations with nutrients or salinity. Florida Bay is thus not a typical estuary due to the unique structure of its mud banks and multiple inputs of metals from the mangrove fringe in the north.     

青藏高原总体输送系数的特征

利用中日亚洲季风机制合作研究计划设在西藏的 4个自动气象站（AWS）获得的5a多（199年7月～1998年12月）时次密集、观测连续的近地层梯度资料,以最小二乘法确定出相应站点各季节的地表粗糙度,并应用廓线-通量法计算了4站逐日的总体输送系数,分析了其随时间的变化特征。结果表明:青藏高原动量输送系数的多年平均值为3.53×10-3～4.99×10-3,热量输送系数为4.67×10-3～6.73×10-3,并且两种输送系数都存在明显的日变化和季节变化,部分站点还存在较明显的年际变化。另外,还讨论了总体输送系数与近地层大气层结稳定度、地表粗糙度以及地面风速等因子的关系,初步建立了可用常规气象站地面观测资料计算青藏高原总体输送系数的拟合公式。     

Narrative warm/cold variations in continental western Europe, AD 708 -1426

An extended narrative dataset of the Medieval time AD 708-1426 in continental western Europe was set up. Some 30-year-moving mean seasonal temperature deviation series were reconstructed. A- warming trend occurred around AD 1200. During the warm stage, seasonal cycle might be weak due to frequent cool summers. Significant warm summer conditions did not occur until the late 14th century, when the annual temperature level began decreasing. The mean warm season temperature level during the late 14th to the early 15th century might be about 0.3°C higher than the present. It was suggested to cautiously comment on historical climates for different seasons.     

黄土与古季风

中国黄土的古季风记录研究，揭示了东亚季风区的环境变迁历史是来自中、高纬大陆的偏北冬季风与来自中、低纬海洋的偏南夏季风的环境效应优势期相互交替的历史。文中简要介绍了有关黄土高原黄土与古季风研究的重要进展，侧重讨论了中原地区末次冰期高分辨率黄土所记录的冬季风和夏季风变迁的特征，最后就今后全球变化计划中的黄土与古季风研究提出了几点意见。     

A Study of Linke Turbidity Factor over Qena / Egypt

Data on instantaneous atmospheric Linke turbidity factor TL (m) are reported for clear days at Qena/Egypt in the period from June 1992 to May 1993.TL(m) is determined using the values of irradiance of direct solar radiation (I),which are calculated from global (G) and diffuse (D) - solar radiation measurements.Monthly and seasonally variations of both diurnal and daily average values of TL (m) increases steadily in the direction of sunset in the months from June to December 1992 as well as Summer and Autumn seasons,while it falls generally in this direction for the months from January to March and Winter season.In April and May,TL (m) fluctuates obviously through the day hours,it is also shown that the average values of TL(m) are particularly large during Summer months compared to other months of the year.This behavior of TL(m) is discussed in view of the variations of some weather elements,which affect the content of water vapor and dust particle in the atmosphere of the study region.It seems t be of s     

1963-2012年中国主要木本植物花期长度时空变化

花期物候变化研究对赏花活动安排、园林景观布置和致敏花粉防治等具有重要意义。现有研究对始花期与盛花期的变化趋势已有较为深刻的认识,但很少有研究辨识了花期长度的时空变化。本文基于“中国物候观测网”观测数据,统计了1963-2012年中国42个站点23种广布木本植物的花期长度变化趋势,分析了花期长度变化的时空格局、种间差异和变化形式。主要结论为：所有的259条花期长度时间序列中,61.39%的序列呈延长趋势,其中显著延长的占21.24%（P<0.05）。灌木花期的延长趋势比乔木更加显著。东北地区南部、华中和华东地区的多数站点花期长度主要呈缩短趋势。在东北地区北部、华北、西南和华南地区,大多数物种的花期长度呈延长趋势。花期长度变化趋势在20°N~22°N间最大（0.94 d/a）。西部地区（87°E~112°E）的花期长度变化趋势（平均0.28 d/a）高于东部地区（平均0.05 d/a）。花期长度的总体变化可分为3个阶段：1963-1980年（偏短）、1981-1997年（与多年平均值接近）和2001-2012年（偏长）,但不同物种的花期长度变化存在显著差异。在花期长度延长的序列中,43.39%是因开花始期提前程度大于开花末期;在花期长度缩短的序列中,62.00%是因开花始期提前程度小于开花末期。