The effect of fractional cloudiness on the oxidation of SO₂     

JAN MATTHIJSEN  KARSTEN SUHRE  PETER BECHTOLD  ROBERT ROSSET 《Tellus. Series B, Chemical and physical meteorology》1997,49(4):343-356

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Weichselian in Sweden before 15,000 B.P.     

JAN LUNDØLVIST 《Boreas: An International Journal of Quaternary Research》1981,10(4):395-402

A brief summary is given of the present state of knowledge about the Weichselian glaciations and interstadials in sweden. The following stages are discussed: (1) The first Weichselian glaciation (W1). This glaciation has not been identified. Probably only northern Sweden was ice-covered. (2) The Jämtland Interstadial , dated at > 50,000 B.P. and correlated with the Finnish Peräpohjola and the Danish Brörup Interstadials. - (3) The second Weichselian glaciation (W II). There are several uncertainteis concerning this glaciation. Sweden was probably ice-covered down to the latitude of Stockholm. – (4) A Middle Weichsedlian interstadial , or complex of interstadials. Some radiocarbon dates indicate, although very uncertain, that most of Sweden may have been free of ice some time rather well known. – Some main problems which have to be investigated are also identified.  相似文献   

Genesis of the Woodstock drumlin field, southern Ontario, Canada     

JAN A. PIOTROWSKI 《Boreas: An International Journal of Quaternary Research》1987,16(3):249-265

The Woodstock drumlin field was formed about 15,000 years ago during the Port Bruce Stadial of the Late Wisconsinan. It consists of three sections, each composed of texturally different till sheets (Tavistock A, B and C Tills) deposited during marginal oscillations of the Huron ice lobe advancing from the Lake Huron depression. A statistically significant relation between till texture and drumlin morphometry has been determined. Features composed of clayey-silt Tavistock A Till are smaller and more elongate than those built up of sandy-silt Tavistock C Till, which reflects a different susceptibility of the drumlin deposits to the moulding action of the glacier. Based on the field data it is suggested that the drumlinizing glacier was temperate all the way up to its margin and basal sliding occurred also at its outermost peripheries. In the drumlin region immediately behind end moraines the shear strength/shear stress ratio was around I and increased progressively in the upstream direction. In the proposed mechanism of drumlin formation the key factor is pore water dissipation (1) through the permeable substratum and (2) into dilatantly expanding granular deposits, both resulting in the necessary increase of the basal till strength.  相似文献   

Glacial history of western Norway 15,000–10,000 B.P.     

JAN MANGERUD  EILIV LARSEN  ODDVAR LONGVA  EIVIND SØNSTEGAARD 《Boreas: An International Journal of Quaternary Research》1979,8(2):179-187

The deglaciation patterns of the Bergen and Nordfjord-Sunnmøre areas in western Norway are described and correlated. In the Bergen area the coast was first deglaciated at 12,600 B.P., with a succeeding re-advance into the North Sea around 12,200 B.P. Later, during the Allerød, the inland ice retreated at least 50 km, but nearly reached the sea again during the Younger Dryas re-advance, ending at 10,000 B.P. Sunnmøre was ice-free during an interstadial 28,000–38,000 B.P. Later the inland ice reached the sea. The final deglaciation is poorly dated in Sunnmøre, while further south in Nordfjord, it started slightly before 12,300 B.P., followed by a major retreat. No large re-advance of the inland ice occurred during the Younger Dryas. However, in the Sunnmøre-Nordfjord area many local glaciers formed outside the inland ice during the Younger Dryas. Limnic sediments outside one such cirque glacier have been cored and dated, proving that the glacier did not exist at 12,300-11,000 B.P., and that it was formed and disappeared in the time interval 11,000–10,000 B.P. (Younger Dryas). The erosion rate of the cirque glacier was 0.9 mm/year.  相似文献   

气候变化对重庆农业的影响及对策研究     

GAO Yanghua  JU Hui  JAN Verhagen  ZHANG Jianping 《四川气象》2008,(4)

本文分析了重庆市气候特点及其对重庆农业的影响;并在全球气候变暖的大气候背景下,分析了重庆气候的变化趋势,并就气候变化对重庆农业可能造成的影响进行了初步的探讨;提出了重庆农业应对气候变化的适应性战略和技术措施。  相似文献   

The Impact of Climate Change on Chongqing Agriculture and the Adaptation Strategy     

JAN Verhagen 《高原山地气象研究》2008,28(4)

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气候变化对重庆农业的影响及对策研究     

高阳华  居辉  JAN Verhagen  唐云辉  张建平 《高原山地气象研究》2008,28(4):46-49

本文分析了重庆市气候特点及其对重庆农业的影响;并在全球气候变暖的大气候背景下,分析了重庆气候的变化趋势,并就气候变化对重庆农业可能造成的影响进行了初步的探讨;提出了重庆农业应对气候变化的适应性战略和技术措施。  相似文献   

IntCal13 calibrated ages of the Vedde and Saksunarvatn ashes and the Younger Dryas boundaries from Kråkenes,western Norway          下载免费PDF全文

ØYSTEIN S. LOHNE  JAN MANGERUD  HILARY H. BIRKS 《第四纪科学杂志》2014,29(5):506-507

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Offshore Absolute Calibration of Space-Borne Radar Altimeters     

GWENAëLE JAN  YVES MÉNARD  MATHILDE FAILLOT  FLORENT LYARD  ERIC JEANSOU  PASCAL BONNEFOND 《Marine Geodesy》2013,36(3-4):615-629

Absolute calibration of sea level measurements collected from space-borne radar altimeters is usually performed with respect to collocated sea level in situ records from tide gauges or GPS buoys (Ménard et al. 1994 Ménard, Y., Jeansou, E. and Vincent, P. 1994. Calibration of the TOPEX-Poseidon altimeters at Lampedusa: Additional results at Harves. J. Geophys Res., 99(C12): 24487–24504. http://dx.doi.org/10.1029%2F94JC01300 [Google Scholar]; Haines et al. 1996 Haines, B. J., Christensen, E. J., Norman, R. A., Parke, M. E., Born, G. H. and Gill, S. K. 1996. Altimeter calibration and geophysical monitoring from collocated measurements at the Harvest oil platform. EOS Trans. Suppl., 77(22): W16 [Google Scholar]; Bonnefond et al. 2003; Haines et al. 2003 Haines, B. J., Dong, D., Born, G. H. and Gill, S. K. 2003. The Harvest experiment: Monitoring Jason-1 and TOPEX/Poseidon from a California offshore platform. Mar. Geod., 26: 239–259. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]; Schum et al. 2003 Schum, C. K., Yi, Y., Cheng, K., Kuo, C., Braun, A., Calmant, S. and Chambers, D. 2003. Calibration of Jason-1 Altimeter over Lake Erie. Mar. Geod., 26: 335–354.  [Google Scholar]; Watson et al. 2003 Watson, C., Coleman, R., White, N., Church, J. and Govind, R. 2003. Absolute calibration of TOPEX/ Poseidon and Jason-1 using GPS buoys in Bass Strait, Australia. Mar. Geod., 26: 285–304. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]; Watson et al. 2004 Watson, C., White, N., Coleman, R., Church, J., Morgan, P. and Govind, R. 2004. TOPEX/Poseidon and Jason-1: Absolute calibration in Bass Strait, Australia. Mar. Geod., 27: 107–131. http://dx.doi.org/10.1080%2F01490410490465373[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]). Such a method allows regular and long-term control of altimetric systems with independent records. However, this approach is based on a single, geographically dependent point. In order to obtain more significant and accurate bias and drift estimates, there is a strong interest in multiplying the number of calibration opportunities. This article describes a method, called the “offshore method” that was developed to extend the single-point approach to a wider regional scale. The principle is to compare altimeter and tide gauge sea level data not only at the point of closest approach of an overflying pass, but also at distant points along adjacent satellite passes. However, connecting sea level satellite measurements with more distant in situ data requires a more accurate determination of the geoid and mean ocean dynamic topography slopes, and also of the ocean dynamical changes. In this demonstration experiment, 10 years of averaged TOPEX/Poseidon mean sea level profiles are used to precisely determine the geoid and the mean ocean circulation slope. The Mog2d barotropic ocean model (Carerre et Lyard 2003 Carrère, L. and Lyard, F. 2003. Modelling the barotropic response of the global ocean to atmospheric wind and pressure forcing-comparisons with observations. GRL, 30(6): 1275 [Google Scholar]) is used to improve our estimate of the ocean dynamics term. The method is first validated with Jason-1 data, off Corsica, where the dedicated calibration site of Senetosa provides independent reference data. The method is then applied to TOPEX/Poseidon on its new orbit and to Geosat Follow On. The results demonstrate that it is feasible to make altimeter calibrations a few tens to hundreds of kilometers away from a dedicated site, as long as accurate mean sea level altimeter profiles can be used to ensure the connection with reference tide gauges.  相似文献   

Model-aided design and optimization of artificial recharge-pumping systems     

ANDREJA JONOSKI  YANGXIAO ZHOU  JAN NONNER  SYLVIE MEIJER 《水文科学杂志》2013,58(6):937-953

Abstract

This paper presents a methodology for the design and optimization of artificial recharge-pumping systems (ARPS). The objective of ARPS is to provide a maximum abstraction rate through artificial recharge, while meeting two operational constraints: (a) the influences of the system operation on groundwater levels should be no more than 25 mm in the vicinity of the system; and (b) the travel time of the infiltrated water from the recharge pond to the pumping wells should be more than 60 days. The combined use of a 3-dimensional generic groundwater simulation model with particle tracking analyses has identified the two best ARPS systems: the circular pond system and the island system. By coupling the simulation model with linear and mixed integer programming optimization, the optimal pumping scheme (number, locations and rates of the pumping wells) has been determined. An unsteady state model has been used to simulate the response of the operation of the two systems under natural seasonal variations. The implementation aspects of the two systems are compared.  相似文献