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Richard Menzel 《Aquatic Sciences - Research Across Boundaries》1946,10(2-3):186-191
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Marvin Lüpke Michael Leuchner Delphis Levia Kazuki Nanko Shin'ichi Iida Annette Menzel 《水文研究》2019,33(26):3391-3406
Forest canopies present irregular surfaces that alter both the quantity and spatiotemporal variability of precipitation inputs. The drop size distribution (DSD) of rainfall varies with rainfall event characteristics and is altered substantially by the forest stand properties. Yet, the influence of two major European tree species, European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) H. Karst), on throughfall DSD is largely unknown. In order to assess the impact of these two species with differing canopy structures on throughfall DSD, two optical disdrometers, one above and one below the canopy of each European beech and Norway spruce, measured DSD of both incident rainfall and throughfall over 2 months at a 10‐s resolution. Fractions of different throughfall categories were analysed for single‐precipitation events of different intensities. While penetrating the canopies, clear shifts in drop size and temporal distributions of incoming rainfall were observed. Beech and spruce, however, had different DSD, behaved differently in their effect on diameter volume percentiles as well as width of drop spectrum. The maximum drop sizes under beech were higher than under spruce. The mean ± standard deviation of the median volume drops size (D50) over all rain events was 2.7 ± 0.28 mm for beech and 0.80 ± 0.04 mm for spruce, respectively. In general, there was a high‐DSD variability within events indicating varying amounts of the different throughfall fractions. These findings help to better understand the effects of different tree species on rainfall partitioning processes and small‐scale variations in subcanopy rainfall inputs, thereby demonstrating the need for further research in high‐resolution spatial and temporal properties of rainfall and throughfall. 相似文献
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Christoph M. Menzel Zsolt Berner Doris Stüben 《Geostandards and Geoanalytical Research》2001,25(2-3):239-251
The applicability of size-exclusion chromatography (SEC) coupled online with a high resolution ICP-MS (HR-ICP-MS) to investigate the speciation of the platinum-group elements (PGE), Rh, Pd and Pt, was evaluated. Experiments were carried out to determine the efficiency of different hydrophilic and hydrophobic size-exclusion gel materials to select the optimal eluent in respect of resolution, recovery, reproducibility and limit of detection. The suitability of HR-ICP-MS as a reliable detection instrument at low pg ml−1 levels was investigated by examining possible mass interferences with Rh, Pd and Pt. Laboratory experiments demonstrated the interaction and capability of forming complexes of humic substances with PGE, demonstrating the potential role of these ubiquitous natural substances in the mobilisation of PGE in the environment. 相似文献
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Plant Phenological Anomalies in Germany and their Relation to Air Temperature and NAO 总被引：13，自引：0，他引：13
Annette Menzel 《Climatic change》2003,57(3):243-263
This paper analyses long-term (1951–2000) phenological observations of20 plant seasonal phases recorded within the phenological network of the German Weather Service in relation to climate data and NAO. Phenological inter-annual variability and temporal trends were determined by using mean anomaly curves for Germany. For all phases, the mean trends derived by this method are similar to German averages of linear trends of single station records. Trend analysis using anomaly curves appears to be effective in relating seasonal phenological trends to climate or satellite data: Spring and summer phenological anomalies, such as leaf unfolding and flowering of different species, strongly correlate with temperature of the preceding months (R2 between 0.65 and 0.85, best one-variable model) andtheir onsets have advanced by 2.5 to 6.7 days per ° C warmer spring. Fruit ripening of Sambucus nigra and Aesculus hippocastanum, keyphenophases of early and mid autumn, correlate well with summer temperature (R2 0.74 and 0.84) and also advance by 6.5and 3.8 days per ° C (April–June). But the response of autumn colouringto warmer climate is more complex because two opposing factors influence autumn colouring dates. Higher spring and early summer temperatures advance leaf colouring, whereas warmer autumn temperatures delay leaf colouring. The percentage of variance explained by temperature (R2 0.22 to 0.51,best one-variable model) is less than for spring and summer phases. The length of the growing season is mainly increased by warmer springs (R2 0.48to 0.64, best one-variable model) and lengthened by 2.4 to 3.5 days/° C (February–April). The North Atlantic Oscillation Index (NAO) of January–March correlates with spring phenological anomalies(R2 0.37 to 0.56, best one-variable model), summer to mid autumn phases respond to NAO of February–March (R2 0.23 to 0.36) (both negativecorrelations). Leaf colouring is delayed by higher NAO of (August) September (R2 0.10to 0.18). NAO of January–February explains 0.41 to 0.44% of thevariance of the length of the growing season. 相似文献
15.
Phenology: Its Importance to the Global Change Community 总被引：10，自引：0，他引：10
Annette Menzel 《Climatic change》2002,54(4):379-385
16.
A camera network with hourly resolution was used to monitor the complex snow processes in montane forest environments. We developed a semi‐automatic procedure to interpret snow depths from the digital images, which exhibited high consistency with manual measurements and station‐based recordings. To extract snow interception dynamics, six binary classification methods were compared. The MaxEntropy classifier demonstrated better performance than the other methods under conditions of varying illumination and was therefore selected as the method used for quantifying snow in tree canopies. Snow accumulation and ablation on the ground, as well as snow loading and unloading in the forest canopies, were investigated using snow parameters derived from the time‐lapse photography monitoring. The influences of meteorologic conditions, forest cover, and elevation on the snow processes were also considered. Time‐lapse photography proved to be an effective and low‐cost approach for collecting useful information on snow processes and facilitating the set‐up of hydrological models. 相似文献
17.
S. K. Deb Steve Wanzong C. S. Velden Inderpreet Kaur C. M. Kishtawal P. K. Pal W. P. Menzel 《Journal of the Indian Society of Remote Sensing》2014,42(4):679-687
The real-time operational use of atmospheric motion vectors (AMVs) at numerical weather prediction (NWP) centers in India are being adversely affected due to inaccurate height assignment of cloud tracers, especially in thin semi-transparent clouds. In India, the operational derivation of AMVs from the Indian geostationary satellite Kalpana-1 began few years ago. A statistical empirical method (SEM) of height assignment, based on a genetic algorithm, is currently used to estimate the height of the retrieved vectors from Kalpana-1. This method has many limitations. In this paper, attempts have been made to implement the widely used and well tested height assignment methods such as the infrared window (WIN) technique, the H2O intercept, and the cloud base method in the Kalpana-1 AMV retrieval algorithm. The new height assignment algorithm significantly improves the statistics of the retrieved winds when compared to radiosondes, especially in high and mid levels winds. 相似文献
18.
In a model project unprecedented in size and scope, Academic Press has made available its 175 scientific journals to licensed
institutions in full-text over the WWW since January 1996. This article describes the unique business model behind this project,
and gives a first evaluation after one year.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
19.
Menzel Peter Teichmann Jakob van den Boogaart Karl Gerald 《Mathematical Geosciences》2020,52(6):731-757
Mathematical Geosciences - Laguerre mosaics have been an important modeling approach in astronomy, physics, crystallography, geology and mathematics for several decades. In materials science, they... 相似文献
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