''Cosmogenic ¹⁰Be ages on the Pomeranian Moraine, Poland'': Comments     

MICHAEL HOUMARK-NIELSEN  SVANTE BJÖRCK  BARBARA WOHLFARTH 《Boreas: An International Journal of Quaternary Research》2006,35(3):600-604

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Heavy metals and sulphur in mosses from southern Spitsbergen   总被引：1，自引：0，他引：1  

KRYSTYNA GRODZINSKA  BARBARA GODZIK 《Polar research》1991,9(2):133-140

Concentrations of Cd, Pb. Ni, Cu. Zn and S were determined in 16 moss species collected from 9 localities in southern Spitsbergen (mostly within the Hornsund region). Two species, Sanionia uncinata and Hylocomium splendens , were objects of more thorough studies. In Sanionia uncinata the mean concentrations were (ug/g): Cd-0.59, Pb-7.07, Ni-4.25, Cu-6.01. Zn-21.13 and S- 1, 481. Hylocomium splendent accumulated similar quantities of these elements. The concentrations of metals and sulphur in mosses differed significantly {p 0 .05) from site to site, depending on geological and climatic conditions specific to the Arctic region. The effect of remote sources of pollution reaching Spitsbergen on the levels of heavy metal concentrations was taken into account, as well as the effect of local emissions from the Polish Polar Station. At 10-25 metre distances from the Station, the levels of heavy metals and sulphur were 3-10 times higher than at a 300-metre distance.  相似文献   

States of maximum entropy production in a one-dimensional vertical model with convective adjustment   总被引：2，自引：0，他引：2  

By TONI PUJOL  JOAQUIM FORT 《地球，A辑:动力气象学与海洋学》2002,54(4):363-369

We investigate the hypothesis that the atmosphere is constrained to maximize its entropy production by using a one-dimensional (1-D) vertical model. We prescribe the lapse rate in the convective layer as that of the standard troposphere. The assumption that convection sustains a critical lapse rate was absent in previous studies, which focused on the vertical distribution of climatic variables, since such a convective adjustment reduces the degrees of freedom of the system and may prevent the application of the maximum entropy production (MEP) principle. This is not the case in the radiative-convective model (RCM) developed here, since we accept a discontinuity of temperatures at the surface similar to that adopted in many RCMs.
For current conditions, the MEP state gives a difference between the ground temperature and the air temperature at the surface ≈10 K. In comparison, conventional RCMs obtain a discontinuity ≈2K only. However, the surface boundary layer velocity in the MEP state appears reasonable (≈m s⁻¹). Moreover, although the convective flux at the surface in MEP states is almost uniform in optically thick atmospheres, it reaches a maximum value for an optical thickness similar to current conditions. This additional result may support the maximum convection hypothesis suggested by Paltridge (1978 ).  相似文献   

A FOOD GEOGRAPHY OF THE GREAT PLAINS     

BARBARA G. SHORTRIDGE 《Geographical review》2003,93(4):507-529

ABSTRACT. This article explores the regional identity of the Great Plains through its foodways using 744 responses from a mailed survey that asked participants to plan a representative menu for their locale. The strongest association is with beef—not surprising in an area known for cattle ranching. Other commonalities include potatoes, beans, and corn. Differentiation within the region is marked by preparation methods for beef as well as emphases on cornbread and peach cobbler in the south, rhubarb pie in the north, tortillas and sopapillas in the southwest, and pickles in two separate clusterings.  相似文献   

Climate over mainland Southeast Asia 10.5–5 ka          下载免费PDF全文

AKKANEEWUT CHABANGBORN  BARBARA WOHLFARTH 《第四纪科学杂志》2014,29(5):445-454

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Large-scale atmospheric circulation changes are associated with the recent loss of Arctic sea ice   总被引：21，自引：0，他引：21  

By JAMES E. OVERLAND  MUYIN WANG 《地球，A辑:动力气象学与海洋学》2010,62(1):1-9

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Suspension and calibration of a sediment trap   总被引：5，自引：0，他引：5  

By Lars Håkanson 《Aquatic Sciences - Research Across Boundaries》1984,46(1):171-175

The aim of this technical note is to introduce a new, simple construction of a buoy-carried, suspended sediment trap that meets given demands concerning design (geometry of vessels) and stability during the registration period. The device is based on a ball-and-socket joint in the center and two Plexiglas cylinders (D=5cm, H=30cm) on PVC plastic arms. The suspension consists of only three parts. To determine the optimal construction, the apparatus has been calibrated in a circulating flume at various water velocities.  相似文献   

运用上月各气象要素的特征来预告下月雨量——(沈阳夏季各月雨量作例)     

杨鉴初  刘钟玲 《气象学报》1953,24(1):159-172

一个地方下月的雨量,能不能从当地上月天气演变的结果所记录下来的各种气象要素的数值来推测呢?现在这篇报告的目的就想解答这个问题。关於这方面的研究,以前早有人注意,例如竺可桢教授研究过冬天温度与夏季雨量的关系,  相似文献   

Intermediate time error growth and predictability: tropics versus mid-latitudes     

By DAVID M. STRAUS  DAN PAOLINO 《地球，A辑:动力气象学与海洋学》2009,61(5):579-586

The evolution of identical twin errors from an atmospheric general circulation model is studied in the linear range (small errors) through intermediate times and the approach to saturation. Between forecast day 1 and 7, the normalized error variance in the tropics is similar to that at higher latitudes. After that, tropical errors grow more slowly. The predictability time τ taken for tropical errors to reach half their saturation values is larger than that for mid-latitudes, especially for the planetary waves, thus implying greater potential predictability in the tropics.
The discrepancy between mid-latitude and tropical τ is more pronounced at 850 hPa than at 200 hPa, is largest for the planetary waves, and is more pronounced for errors arising from wave phase differences (than from wave amplitude differences).
The spectra of the error in 200 hPa zonal wind show that for forecast times up to about 5 d, the tropical error peaks at much shorter scales than the mid-latitude errors, but that subsequently tropical and mid-latitude error spectra look increasingly similar.
The difference between upper and lower level tropical τ may be due to the greater influence of mid-latitudes at the upper levels.  相似文献   

On the selection of prognostic moments in parametrization schemes for drop sedimentation     

By ULRIKE WACKER  CHRISTOF LÜPKES 《地球，A辑:动力气象学与海洋学》2009,61(4):498-511

Common parametrization models for cloud microphysical processes use condensate mass density and/or particle number density as prognostic properties. However, other moments of the particle size distribution can likewise be chosen for prediction. This study deals with parametrization models with one and two, respectively, prognostic moments for the sedimentation of drop ensembles. The spectral resolving model defines the reference solution.
The evolution of the vertical profiles of liquid water content, drop number density and rain rate strongly depend on the choice of the prognostic moments in the parametrization models. In models with a single prognostic moment, its vertical profile is copied by all other moments. The moment of most physical pertinence is recommended for prediction. In models with two prognostic moments, the vertical profiles of all moments differ. The orders of the prognostic moments should be chosen close to the order of moments of highest relevance. Otherwise large errors occur. For example, comparison of modelled versus observed radar reflectivity (6th moment with respect to diameter) does not tell much about the quality of other properties if reflectivity is diagnosed from for example, number density and mass density. Furthermore, mass conservation is fulfilled only if mass density is forecasted.  相似文献