Some results about the relation between an objective front parameter and cloud bands in satellite images and its connection to classical cold front models     

Dr. V. Zwatz-Meise  Dr. F. Hufnagl 《Meteorology and Atmospheric Physics》1990,42(1):77-89

Summary Two different manifestations of cold fronts are compared: an objective front parameter (the thermal front parameter =TFP) which locates a front where the maximal change of the temperature (thickness) gradient appears and the cloud band in the satellite images. TheTFP is merely a line while the cloud band is mostly several hundred kilometers broad. The relation between the position of theTFP and the cloud band is investigated statistically using all cold front events of one year. It can be shown that theTFP prefers special positions relative to the cloud band and that these positions remain constant during the next 12 hours in a high number of cases. This confirms the usefulness of its diagnosis and very short range prognosis as is done with an operationally issued satellite report (Satrep). Vertical cross sections of equivalent potential temperature and humidity with some parameters superimposed show a connection between the position of theTFP relative to the cloud band and the classical cold front models of the ana-and katafront.With 8 Figures  相似文献   

Statistische Untersuchungen über das Precipitable Water über Wien und die Änderungen desselben bei Niederschlägen     

Dr. Veronika Meise 《Meteorology and Atmospheric Physics》1973,22(1):71-96

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Using a decadal diatom sediment trap record to unravel seasonal processes important for the formation of the sedimentary diatom signal     

Dominique Béatrice Maier  Veronika Gälman  Ingemar Renberg  Christian Bigler 《Journal of Paleolimnology》2018,60(2):133-152

Sediment trap studies and high frequency monitoring are of great importance to develop a deeper understanding of how seasonal environmental processes are imprinted in sediment signal formation. We collected whole year diatom assemblages from 2002 to 2014 with a sequential sediment trap from a varved boreal lake (Nylandssjön, Sweden) together with environmental and limnological parameters, and compared them with the corresponding diatom record of the annual laminated sediment. Our data set indicates a large year-to-year variability of diatom succession and abundance patterns, which is well reflected in the varved sediments. Specifically, Cyclotella glomerata dominated the annual sediment trap record (as well as in the corresponding sediment varves) in years with warmer air temperatures in March/April, and Asterionella formosa dominated the annual sediment assemblages as a consequence of years characterized by higher runoff before lake over-turn. Years succeeding forest clearance in the lake catchment showed marked increase in diatom and sediment flux. The DCA scores of the yearly diatom trap assemblages clearly resemble the lake’s thermal structure, which indicates that the relative abundance of major taxa seems primarily controlled by the timing of seasonal environmental events, such as above-average winter air temperature and/or autumn runoff and the current thermal structure of the lake. The high seasonal variability between environmental drivers in combination with the physical limnology leaves us with several possible scenarios leading to either an A. formosa versus C. glomerata dominated annual diatom sediment signal. With this study we highlight that short-term environmental events and seasonal limnological conditions are of major importance for interpreting annual sediment signals.  相似文献