Broder Merkel

Prof. Broder Merkel

Universität Bergakademie Freiberg, Institute for Geology, Freiberg, Germany
orcid

Research Focus & Metrics

Academic Career Length

28Years (1999-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 September 2015 in Remote Sensing
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SGShimelis Berhanu Gebere
Shimelis Berhanu Gebere
Tena Alamirew AgumassieTena Alamirew Agumassie
Tena Alamirew Agumassie
Broder MerkelBroder Merkel
Broder Merkel
Assefa MelesseAssefa Melesse
Assefa Melesse
Accurate estimation of rainfall in mountainous areas is necessary for various water resource-related applications. Though rain gauges accurately measure rainfall, they are rarely found in mountainous regions and satellite rainfall data can be used as an alternative source over these regions. This study evaluated the performance of three high-resolution satellite rainfall products, the Tropical Rainfall Measuring Mission (TRMM 3B42), the Global Satellite Mapping of Precipitation (GSMaP_MVK+), and the Precipitation Estimation from Remotely-Sensed Information using Artificial Neural Networks (PERSIANN) at daily, monthly, and seasonal time scales against rain gauge records over data-scarce parts of Eastern Ethiopia. TRMM 3B42 rain products show relatively better performance at the three time scales, while PERSIANN did much better than GSMaP. At the daily time scale, TRMM correctly detected 88% of the rainfall from the rain gauge. The correlation at the monthly time scale also revealed that the TRMM has captured the observed rainfall better than the other two. For Belg (short rain) and Kiremt (long rain) seasons, the TRMM did better than the others by far. However, during Bega (dry) season, PERSIANN showed a relatively good estimate. At all-time scales, noticing the bias, TRMM tends to overestimate, while PERSIANN and GSMaP tend to underestimate the rainfall. The overall result suggests that monthly and seasonal TRMM rainfall performed better than daily rainfall. It has also been found that both GSMaP and PERSIANN performed better in relatively flat areas than mountainous areas. Before the practical use of TRMM, the RMSE value needs to be improved by considering the topography of the study area or adjusting the bias.

24 July 2013 in Arabian Journal of Geosciences
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MKMohammed Khattab
Mohammed Khattab
Broder MerkelBroder Merkel
Broder Merkel

13 March 2009 in Environmental Earth Sciences
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KZKetema Zeleke
Ketema Zeleke
Broder MerkelBroder Merkel
Broder Merkel

19 December 2012 in Environmental Earth Sciences
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Mehdi ZareiMehdi Zarei
Mehdi Zarei
EREzzat Raeisi
Ezzat Raeisi
Broder MerkelBroder Merkel
Broder Merkel
NKNicolai-Alexeji Kummer
Nicolai-Alexeji Kummer

6 March 2014 in Scientific Reports
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Journal Article
Open access
TPThomas Pohl
Thomas Pohl
SASameh W. Al-Muqdadi
Sameh W. Al-Muqdadi
MAMalik H. Ali
Malik H. Ali
NFNadia Al-Mudaffar Fawzi
Nadia Al-Mudaffar Fawzi
HEHermann Ehrlich
Hermann Ehrlich
Broder MerkelBroder Merkel
Broder Merkel
Until now, it has been well-established that coral complex in the Arabian/Persian Gulf only exist in the coastal regions of Bahrain, Iran, Kuwait, Oman, Qatar, Saudi Arabia, and United Arab Emirates and it was thought that there are no coral reefs in Iraq. However, here for the first time we show the existence of a living 28[emsp14]km2 large coral reef in this country. These corals are adapted to one of the most extreme coral-bearing environments on earth: the seawater temperature in this area ranges between 14 and 34[deg]C. The discovery of the unique coral reef oasis in the turbid coastal waters of Iraq will stimulate the interest of governmental agencies, environmental organizations, as well as of the international scientific community working on the fundamental understanding of coral marine ecosystems and global climate today.

14 April 2015 in Geosciences
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MHMandy Hoyer
Mandy Hoyer
NKNicolai Kummer
Nicolai Kummer
Broder MerkelBroder Merkel
Broder Merkel
Li sorption was studied on natural bentonite, kaolin and zeolite in batch experiments at variable Li and Na concentrations (0, 1.5, 15, 150, 750 mM LiCl and 0.01, 0.1, 1, 3, 5 M NaCl). The solid-to-solution ratio was 1:4 and pH ranged from 2 to 10. Maximum Li sorption was determined at 0.01 M NaCl and 750 mM LiCl concentration in solution. It was 3800 ± 380 ppm, 1300 ± 130 ppm and 3900 ± 390 ppm on bentonite, kaolin and zeolite, respectively, which is in the average to upper range typical for clay minerals. Under these conditions, kaolin was saturated with Li, whereas Li in bentonite and zeolite occupied only about 55%–79% and 9%–26% of the typical cation exchange capacity (CEC) of smectites and zeolites, respectively. This is explained by differences in the way Li is bound in the materials studied. Li sorption on bentonite was independent of pH due to strong pH buffering. Above pH 5, kaolin was transformed to gibbsite, which completely changed its Li sorption capabilities. Extremely low as well as extremely high pH destabilized the crystal lattice of zeolite. All in all it was shown that, under the studied conditions, Li sorption on the studied materials occurs in detectable quantities. So, clay minerals and zeolites can act as a sink for Li if Li concentrations in solution are sufficiently high.