中国省区经济增长空间分布动态

采用分布动态方法(MEDD), 从省区经济增长空间分布的形状和流动性两方面考察1978-2004 年中国省区经济增长空间分布的动态演进, 结果表明, 中国省区经济增长的空间分布形态经历多极化-收敛-双峰状的变化过程, 其中, 俱乐部收敛省区内部的经济发展差距由扩大到再次缩小, 俱乐部间的发展差距由缩小到再次扩大, 说明收敛俱乐部间的经济差距在扩大。1990 年后, 地区经济增长的活跃性提高; 转移概率矩阵、无条件和空间条件动态随机核估计及密度等高线图显示空间相互作用影响着省区经济增长未来的空间分布, 空间因素是影响地区经济增长分布的重要因素, 相邻地区经济增长互相依赖, 因地理位置临近所产生的空间溢出效应促使了相似经济水平地区的空间聚集。     

Hydro-climatological changes in the Colorado River Basin over a century

This study evaluates changes in streamflow, temperature and precipitation over a time span of 105 years (1906–2010) in the Colorado River Basin (CRB). Monthly precipitation and temperature data for 29 climate divisions, and streamflow data for 29 naturalized gauges were analyzed. Two variations of the Mann-Kendall test, considering lag-1 auto correlation and long-term persistence, and the Pettitt test were employed to assess trends and shifts, respectively. Results indicated that streamflow increased during the winter–spring months and decreased during the summer– autumn period. Decreasing trends in winter precipitation were identified over snow-dominated regions in the upper basin. Significant increases in temperature were detected over several months. Major shifts were noticed in 1964, 1968 and in the late 1920s. Increasing temperature while decreasing streamflow and precipitation were noticed after major shifts in the 1930s, and these shifts coincided with coupled phases of El Niño Southern Oscillation and Pacific Decadal Oscillation.

EDITOR A. Castellarin; ASSOCIATE EDITOR R. Hirsch     

东亚季风边缘区气候代用指标的分形比较及其意义

利用R/S分析东亚季风边缘区祁连山教德冰心、树木车轮、黄土磁化率、CaCO3含量曲线,得到其分维值分别为1．29、1．30、1．19和1．15,证实近百万年来东亚率风演变的特征是长期持续的,即季风边缘区具有干净化趋势,且旱化趋势的成分更为明显。其中,冰心δ18O比率、年轮指数的分维数与乌鞘岭年平均温度记录的分维值1．25接近,黄土磁化率和CaCO3含量的分维数与年降水量记录的分维值1．19一致。虽然这些气候指标是用不同物理单位测量并在不同时间尺度记录的,但分形分析可对它们进行数学比较,从而揭示出不同信息源所包含的气候意义。     

海南东方近岸海域海浪观测特征研究

利用海南东方近岸海域2014年至2015年间一整年的海浪观测资料, 分析了海浪的时间变化特征。观测时间段内, 有效波高最大值为4.03m, 平均值0.79m; 平均周期最大值为6.32s, 平均值为3.58s。该海域冬季波高较大, 秋季最小, 常浪向为SSW方向, 强浪向为WSW向。基于该长期观测数据, 文章亦研究了平均周期、有效波高之间的关系, 同时还确立了该海域波高与平均持续时间之间的关系。最后讨论了观测时间段内波浪能流密度的变化特征, 发现一年中能流密度大于2kW·m^-1的频率为26%, 且从全年的计算结果来看, 观测位置处12月的波浪能较适宜开发, 但总体波浪能资源不够丰富。文章对于认识海南东方近岸海域波浪特征以及工程设计都具有重要的意义。     

Fish persistence and fluvial geomorphology in central Australia

The purposes of this paper are to document the composition and distribution of fishes in the Alice Springs region of Australia, and discuss constraints on fish persistence in this arid region. Nine native and six exotic species were recorded; most exotics no longer exist. Except in Finke River, only one or no native species were found. Fish survival in the area is ameliorated by the exceptionally broad environmental tolerances and migratory abilities of many species, but ultimately depends upon the effects of geology, geomorphology, and the vagaries in pattern of sediment transport on water persistence.     

From small scales to the big picture: persistence mechanisms of planktonic grazers in the oligotrophic ocean

In this review we evaluate whether universal behavioral and metabolic mechanisms exist, which permit marine proto‐ and metazooplankton to persist in continuously food‐limited environments such as the North Pacific Subtropical Gyre and other oligotrophic ocean systems. We re‐visit the issue of what processes account for low steady‐state abundance of the dominant groups of planktonic grazers: phagotrophic protists and copepods, by examining evidence for the four processes proposed by Strom et al. (2000) : grazing thresholds, behavioral response to prey patchiness, top–down control of grazers, and mixotrophy (combination of photosynthesis and phagotrophy in protists) and/or omnivory (switching between alternate prey types). Published observations reveal that grazing thresholds, below which feeders reduce their feeding efforts and, with that, their metabolic expenditures, do exist. There are also studies suggesting that both protistan and small metazoan plankton feeders may take advantage of patchiness of food particles and are frequently mixotrophic and/or omnivorous. Predator patchiness in response to prey patches may facilitate top–down control of grazers. Finally, we discuss processes, which may lead to low quasi steady‐state abundances of food particles and feeders.     

A general Bayesian framework for calibrating and evaluating stochastic models of annual multi-site hydrological data

Multi-site simulation of hydrological data are required for drought risk assessment of large multi-reservoir water supply systems. In this paper, a general Bayesian framework is presented for the calibration and evaluation of multi-site hydrological data at annual timescales. Models included within this framework are the hidden Markov model (HMM) and the widely used lag-1 autoregressive (AR(1)) model. These models are extended by the inclusion of a Box–Cox transformation and a spatial correlation function in a multi-site setting. Parameter uncertainty is evaluated using Markov chain Monte Carlo techniques. Models are evaluated by their ability to reproduce a range of important extreme statistics and compared using Bayesian model selection techniques which evaluate model probabilities. The case study, using multi-site annual rainfall data situated within catchments which contribute to Sydney’s main water supply, provided the following results: Firstly, in terms of model probabilities and diagnostics, the inclusion of the Box–Cox transformation was preferred. Secondly the AR(1) and HMM performed similarly, while some other proposed AR(1)/HMM models with regionally pooled parameters had greater posterior probability than these two models. The practical significance of parameter and model uncertainty was illustrated using a case study involving drought security analysis for urban water supply. It was shown that ignoring parameter uncertainty resulted in a significant overestimate of reservoir yield and an underestimation of system vulnerability to severe drought.     

中国区域干旱的持续性特征研究

利用1961-2012年中国区域586个气象站的降水、气温、日照时数、相对湿度、风速等资料计算了逐月K干旱指数, 在此基础上, 对全国16个区的干旱持续性特征进行了研究. 结果表明: 华北、河套、西北地区东部、西南地区北部、黄淮及新疆南部地区干旱的持续性较强, 常发生3个月以上的长期干旱过程, 并且容易在旱情解除后的短期内(1个月)再次出现干旱; 而南方、东北和新疆北部地区干旱的持续性较弱, 以1个月的短期干旱为主, 且干旱过程之间的时间间隔相对较长, 大多为3个月以上; 华北、河套、西北地区东部、西南地区北部和南部、以及华南地区的干旱过程在冬、秋季开始的频次最高, 且大部分在春季结束, 而冬、春两季的干旱明显比夏、秋两季偏多. 100°E以西(新疆北部除外)的广大地区干旱过程的开始时间主要集中在秋季, 结束时间集中在春、冬两季; 同时, 冬季和秋季干旱多发, 其次是春季, 夏季出现的干旱频次最少.     

The scientific legacy of Harold Edwin Hurst (1880–1978)

ABSTRACT

Emanating from his remarkable characterization of long-term variability in geophysical records in the early 1950s, Hurst’s scientific legacy to hydrology and other disciplines is explored. A statistical explanation of the so-called “Hurst Phenomenon” did not emerge until 1968 when Mandelbrot and co-authors proposed fractional Gaussian noise based on the hypothesis of infinite memory. A vibrant hydrological literature ensued where alternative modelling representations were explored and debated, e.g. ARMA models, the Broken Line model, shifting mean models with no memory, FARIMA models, and Hurst-Kolmogorov dynamics, acknowledging a link with the work of Kolmogorov in 1940. The diffusion of Hurst’s work beyond hydrology is summarized by discipline and citations, showing that he arguably has the largest scientific footprint of any hydrologist in the last century. Its particular relevance to the modelling of long-term climatic variability in the era of climate change is discussed. Links to various long-term modes of variability in the climate system, driven by fluctuations in sea surface temperatures and ocean dynamics, are explored. Several issues related to the Hurst Phenomenon in hydrology remain as a challenge for future research.

Editor M. Acreman; Associate editor A. Carsteanu