Recent warming in the Yellow/East China Sea during winter and the associated atmospheric circulation

We examine characteristics in the variability of sea surface temperature (SST) in the Yellow/East China Sea during the boreal winter (December–January–February) for the period 1950–2008 in observations. It is found that the mean SST in the Yellow Sea/East China Sea gradually increases during recent decades. A warming trend of a basin scale SST is significant in most of the regions in the Yellow/East Sea, which is well explained by the variability of the first empirical orthogonal function SST mode. We suggest one candidate mechanism that the North Pacific oscillation (NPO)-like sea level pressure play an important role to warm the Yellow/East China Sea. Anomalous anticyclonic circulation, which is the southern lobe of NPO-like sea level pressure over the North Pacific, causes a weakening of northerly mean winds over the Yellow/East China Sea during winter. This contributes to increase in the SST in the Yellow/East China Sea through the changes in the latent heat and sensible heat fluxes.     

塔里木盆地巴麦地区石炭系低速异常碳酸盐岩的解释

巴麦地区即塔西南巴楚隆起-麦盖提斜坡,具有台地边缘-斜坡的古构造和古地理背景,这种台地边缘和典型的浅滩沉积暗示了该区具有发育生物礁的环境特征。区内先巴扎（XBZ）600 km²三维地震探区石炭系发育了巴楚组（C₁b）生屑灰岩及标准灰岩、小海子组（C₂x）3套灰岩,其中小海子组发现特殊响应碳酸盐岩,主要表现为厚度增大、频率增高、多出一条波峰同相轴的地震响应特征。通过差异厚度法、底面拉平法、地震属性法、正反演模型法,结合野外露头、岩心、镜下观察、录井、沉积相等综合分析,可初步推测该低速异常体为厚度增加、孔隙度增大的近东西向台地边缘障壁礁所致。礁体东西走向延伸超过25 km,礁核区小海子组灰岩最厚62 m,礁外的小海子组50 m。台缘斜坡南倾,坡度陡,水平宽度1~2 km。礁后生屑滩北倾,坡度缓,水平宽度3~6 km。受色力布亚断裂带遮挡,该生物礁储层可以形成有利圈闭,面积约为42 km²,厚约45 m。     

APPARENT RESISTIVITY TEMPORAL VARIATION CHARAC-TERISTICS AFFECTED BY THE FIXED DISTURBANCE SOURCE ON SURFACE OF MEASURING AREA

Current leakage,metallic conductor,and local anomalous resistivity body are main disturbance sources which affect the successive observation of apparent resistivity in stations,besides the observing system failure.We construct a finite element model using a 3-layered horizontal medium to discuss the dynamic characteristics of disturbances caused by metal conductor and local anomalous resistivity body in the measuring filed.The numerical results show that low resistivity source which is located in areas where the sensitivity coefficient is positive will cause decline on apparent resistivity observation.While low resistivity source will cause increase when it is located in areas where the sensitivity coefficient is negative.Disturbance caused by high resistivity source is opposite to the one from low resistivity source.The general dynamic feature of disturbance is that the disturbance amplitude increases as the resistivity of shallow layer decreases,while the amplitude declines when the shallow layer's resistivity increases.For the measuring direction which has normal annual variation form,low resistivity source which is located in area where the sensitivity coefficient is positive will increase the annual variation amplitude,while it will reduce annual amplitude when it is in a negative sensitivity coefficient area.Annual amplitude changes caused by high resistivity source are opposite to the changes caused by low resistivity source.For the measuring direction which has abnormal annual variation form,dynamic annual feature is opposite to the one in direction of normal annual variation form.If the dynamic feature is opposite to the annual variation and disturbance amplitude is also greater than annual amplitude,the annual variation will change direction.Disturbance amplitude from metallic conductor is affected by the resistivity and cross-section area,the lower of the resistivity and the larger of the cross-section area,the greater of the disturbance amplitude.     

Causes and effects of spatial and temporal variations of cold period in Chinese oases between 1960 and 2014

Based on daily average temperatures and observation data from 74 meteorological stations in Chinese oases, we calculate five-day (pentad) average temperature ≤0°C for the start and end pentad as well as pentads of cold period using linear regression analysis, nonparametric Mann-Kendall tests, the Morlet wavelet power spectrum, and correlation analysis. We also analyze spatial and temporal variations and their effects on the start and end pentad as well as pentads of cold period in Chinese oases. Results show that over the last 55 years, the start pentad of cold period has been postponed while the end pentad has been advanced. Overall, the pentads have gradually shortened over time at trend rates that are 0.3 p/10a,–0.27 p/10a, and–0.58 p/10a, respectively. Spatial differences are significant, especially for the Qaidam Basin oasis where the start pentad is the earliest, the end pentad is the latest, and the trend of change is most obvious. Mutation points for the start and end pentad as well as pentads of cold period were observed in 1990, 1998, and 1994, respectively. Of these, the start pentad and pentads of cold period show a periodic cycle, related to atmospheric circulation and El Nino events, while the end pentad exhibits a periodic cycle, related to solar activity. The Tibetan Plateau index (TPI), the Asian polar vortex area index (APVAI), and carbon dioxide emissions (CDE) are the main factors affecting cold period in the study area, whereas the South Asian summer monsoon (SASM) index exerts the greatest effect on the Qaidam Basin oasis. The start and end pentad as well as pentads of cold period increase in concert with latitude, longitude, and altitude; in response to these changes, the start pentad is advanced, the end pentad is postponed, and pentads of cold period are gradually extended. Results show that change in latitude is most significant. Overall, the start and end pentad as well as pentads of cold period show clear responses to regional warming, but there are different effects on each.     

1880―2015 年汕头降水量变化趋势与全球气候变暖的关系

根据汕头气象站 1880―2015 年逐月降水量资料,采用滤波、线性倾向计算、趋势系数计算、相关分析、谱分析等方法,分析该站近 135 a 来降水量的变化趋势及其与全球气候变暖的关系,结果得出：1）汕头站近 135a 来的全年及前汛期、后汛期的降水量变化存在 2~7、10 和 30 a 左右的周期变化,没有显著的上升或下降趋势;2）近 135 a 来汕头的降水量变化与同期全球气候变暖对应关系较为复杂,暖期（1977―2015 年）与冷期（1900―1938 年）相比,汛期（4―9 月）雨量增加 68.1 mm,其他月份（旱期）减少 64.1 mm,年雨量仅增加 4 mm;3）按现用广东省气象局降水气候评价标准,全球气候变暖背景下汕头前汛期降水量正常年景的频率增加、后汛期降水量偏少的概率增多。     

生物灭绝与人类存亡

近代由于气候的变暖,工业化进程的加快,人口的激增,森林的过度砍伐,草场的超载过牧,化学制品的滥用,环境的污染,生态环境遭到了严重破坏,生物物种灭绝速度较单纯自然状态下的速度要快1000倍。生物物种灭绝对人类生产、生活,甚至对人类生存都构成巨大的威胁。因此,应对气候变化,保护生物多样性,防止物种灭绝,已成为全球性的紧迫任务;中国是世界生物物种资源最丰富的国家之一。中国生物多样性形势总体严峻。中国政府高度重视生物多样性保护工作,先后颁布一系列法律法规,已收到巨大成效;保护生物多样性确保世界粮食安全,是全球人民的普遍愿望。生物灭绝关系人类存亡。人类要秉承天人合一的理念,与大自然和谐相处。     

Differential modulation of eastern oyster (<Emphasis Type="Italic">Crassostrea virginica</Emphasis>) disease parasites by the El-Niño-Southern Oscillation and the North Atlantic Oscillation

The eastern oyster (Crassostrea virginica) is affected by two protozoan parasites, Perkinsus marinus which causes Dermo disease and Haplosporidium nelsoni which causes MSX (Multinucleated Sphere Unknown) disease. Both diseases are largely controlled by water temperature and salinity and thus are potentially sensitive to climate variations resulting from the El Niño-Southern Oscillation (ENSO), which influences climate along the Gulf of Mexico coast, and the North Atlantic Oscillation (NAO), which influences climate along the Atlantic coast of the United States. In this study, a 10-year time series of temperature and salinity and P. marinus infection intensity for a site in Louisiana on the Gulf of Mexico coast and a 52-year time series of air temperature and freshwater inflow and oyster mortality from Delaware Bay on the Atlantic coast of the United States were analyzed to determine patterns in disease and disease-induced mortality in C. virginica populations that resulted from ENSO and NAO climate variations. Wavelet analysis was used to decompose the environmental, disease infection intensity and oyster mortality time series into a time–frequency space to determine the dominant modes of variability and the time variability of the modes. For the Louisiana site, salinity and Dermo disease infection intensity are correlated at a periodicity of 4 years, which corresponds to ENSO. The influence of ENSO on Dermo disease along the Gulf of Mexico is through its effect on salinity, with high salinity, which occurs during the La Niña phase of ENSO at this location, favoring parasite proliferation. For the Delaware Bay site, the primary correlation was between temperature and oyster mortality, with a periodicity of 8 years, which corresponds to the NAO. Warmer temperatures, which occur during the positive phase of the NAO, favor the parasites causing increased oyster mortality. Thus, disease prevalence and intensity in C. virginica populations along the Gulf of Mexico coast is primarily regulated by salinity, whereas temperature regulates the disease process along the United States east coast. These results show that the response of an organism to climate variability in a region is not indicative of the response that will occur over the entire range of a particular species. This has important implications for management of marine resources, especially those that are commercially harvested.     

Discussion of “Neuro-fuzzy models employing wavelet analysis for suspended sediment concentration prediction in rivers”

Citation Abrahart, R.J. & Mount, N.J. (2011) Discussion of “Neuro-fuzzy models employing wavelet analysis for suspended sediment concentration prediction in rivers by S.A. Mirgagheri et al. (2010, Hydrol. Sci. J. 55(7), 1175–1189).” Hydrol. Sci. J. 56(7), 1325–1329.     

Projection of future world water resources under SRES scenarios: an integrated assessment

Abstract

Changes in water resources availability, as affected by global climate warming, together with changes in water withdrawal, could influence the world water resources stress situation. In this study, we investigate how the world water resources situation will likely change under the Special Report on Emissions Scenarios (SRES) by integrating water withdrawal projections. First, the potential changes in water resources availability are investigated by a multi-model analysis of the ensemble outputs of six general circulation models (GCMs) from organizations worldwide. The analysis suggests that, while climate warming might increase water resources availability to human society, there is a large discrepancy in the size of the water resource depending on the GCM used. Secondly, the changes in water-stressed basins and the number of people living in them are evaluated by two indices at the basin scale. The numbers were projected to increase in the future and possibly to be doubled in the 2050s for the three SRES scenarios A1b, A2 and B1. Finally, the relative impacts of population growth, water use change and climate warming on world water resources are investigated using the global highly water-stressed population as an overall indicator. The results suggest that population and socio-economic development are the major drivers of growing world water resources stress. Even though water availability was projected to increase under different warming scenarios, the reduction of world water stress is very limited. The principal alternative to sustainable governance of world water resources is to improve water-use efficiency globally by effectively reducing net water withdrawal.

Editor Z.W. Kundzewicz; Associate editor D. Gerten     

Global projections of changing risks of floods and droughts in a changing climate

Abstract

Simulated daily discharge derived from a relatively high-resolution (approximately 1.1-degree) general circulation model was used to investigate future projections of extremes in river discharge under global warming. The frequency of floods was projected to increase over many regions, except those including North America and central to western Eurasia. The drought frequency was projected to increase globally, while regions such as northern high latitudes, eastern Australia, and eastern Eurasia showed a decrease or no significant changes. Changes in flood and drought are not explained simply by changes in annual precipitation, heavy precipitation, or differences between precipitation and evapotranspiration. Several regions were projected to have increases in both flood frequency and drought frequency. Such regions show a decrease in the number of precipitation days, but an increase in days with heavy rain. Several regions show shifts in the flood season from springtime snowmelt to the summer period of heavy precipitation.