Insolation over the Arabian Sea during the southwest monsoon     

P. V. Hareesh Kumar  N. Mohan Kumar  Basil Mathew 《Boundary-Layer Meteorology》1991,56(1-2):197-203

The relationship between monsoon cloud cover and incoming solar radiation in the Arabian Sea is examined utilising the available observations of daily mean total cloud amount and solar radiation collected during the summer monsoon. With these data sets, various cloud correction formulae are evaluated. For the estimation of solar radiation, the formulation of Laevastu (1960) is best, with a minimum error of -4%. A multiple polynomial regression equation based on cloud cover and noon altitude of the sun is developed for estimation of daily radiation. The error between estimated and observed radiation is -2%.  相似文献   

Mitigation of the seismic motion near the edge of cliff-type topographies   总被引：1，自引：0，他引：1  

C.A. Stamatopoulos  M. Bassanou  A.J. Brennan  G. Madabhushi 《Soil Dynamics and Earthquake Engineering》2007,27(12):1082-1100

Concentration of damage of buildings near the edge of hard or dense cliff-type topographies has been observed during a number of recent earthquakes. These observations have been interpreted by numerical dynamic analyses that illustrate the amplification of accelerations near the edge of slopes. The paper studies the effect of mitigating these accelerations using anchors both experimentally and numerically. The main issue is that if the part of the slope in which topographic amplification occurs is connected to that in which the acceleration is less, then the accelerations have to become more uniform. The experimental study involves dynamic centrifuge tests at the Cambridge University facility both with and without anchors. The numerical procedure was verified by the seismic response of the centrifuge tests. It was then applied to the study of the effect of anchors of a typical field case, the Aegion slope, under two different input motions. In all cases anchors were found effective in mitigating the seismic motion near the edge.  相似文献   

Institutions,indigenous peoples,and climate change adaptation in the Canadian Arctic     

Vogel  Brennan  Bullock  Ryan C. L. 《GeoJournal》2021,86(6):2555-2572

GeoJournal - Climate change impacts on Indigenous peoples in remote regions pose unique institutional challenges and opportunities for governments. Reducing vulnerability and enabling collaborative...  相似文献   

India at crossroads for energy     

Mu Ramkumar  M.Santosh  Manoj J.Mathew  Numair A.Siddiqui 《地学前缘(英文版)》2021,12(6):356-360

As one of the fastest growing economies and further larger consumer of energy in the world,there has been a paradigm shift in India's energy demand.Here we evaluate the growth of Indian economy its,diversification of agriculture-based economy to industrial production,service and digital-technology based economy and deepening of income sources,although the dependence on foreign sources for energy demands has not markedly improved.This situation has placed India at the crossroads for energy sufficiency,especially under the highly fluid and changing geopolitical,strategic,environmental and economic scenarios of the World order.We attempt to un-derstand the issue from geological perspective and address some of the impediments.  相似文献   

Constraints on surface deformation in the Seattle, WA, urban corridor from satellite radar interferometry time-series analysis     

Noah J. Finnegan  Mathew E. Pritchard  Rowena B. Lohman  Paul R. Lundgren 《Geophysical Journal International》2008,174(1):29-41

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Persistent weak thermal stratification inhibits mixing in the epilimnion of north-temperate Lake Opeongo,Canada     

Patricia Pernica  Mathew G. Wells  Sally MacIntyre 《Aquatic Sciences - Research Across Boundaries》2014,76(2):187-201

Persistent weak temperature stratification characterizes the epilimnion of Lake Opeongo, Ontario, Canada, and reduces the magnitude of turbulent mixing. Throughout July and August 2009, the epilimnion was isothermal for only 34 % of the record, while for 28 % of the record there was at least a 2 °C temperature difference across the 5 m deep epilimnion. During these stratified periods, there were increases in gradient Richardson numbers (Ri _g ), and decreases in rates of dissipation of turbulent kinetic energy ( $\varepsilon$ ), the turbulence activity parameter (I = ε/νN ²), an indicator of active mixing, and vertical eddy diffusivity (K _z ) inferred from temperature microstructure profiles. During periods of shear induced mixing, values of ε approached 10^?6 m² s^?3 and decreased during periods of increasing Ri _g . For 0 < Ri _g  < 1, average values of I were ~1,000 and values of K _z were slightly higher than 10^?4 m² s^?1. For Ri _g >1, average values of I were ~300 and K _z was reduced by one to three orders of magnitude. Mixing during cold fronts occurred over time scales of minutes to hours, which worked to erode diurnal thermoclines. However, during periods of persistent secondary thermoclines, mixing was suppressed throughout the epilimnion.  相似文献   

Generic hierarchy of sandstone facies quality and static connectivity: an example from the Middle-Late Miocene Miri Formation,Sarawak Basin,Borneo     

Numair A. Siddiqui  Abdul Hadi A. Rahman  Chow W. Sum  Manoj J. Mathew  Muhammad Hassaan  David Menier 《Arabian Journal of Geosciences》2017,10(11):237

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Sediment dynamics and transport regimes in a narrow microtidal estuary     

Mathew  Rooni  Winterwerp  Johan C. 《Ocean Dynamics》2020,70(4):435-462

Ocean Dynamics - Estuarine sediment dynamics are a consequence of various forcings (barotropic, estuarine circulation, and fluvial) that vary in space and time. Here, we present a study examining...  相似文献   

Automating Recession Curve Displacement Recharge Estimation          下载免费PDF全文

Brennan Smith  Stuart Schwartz 《Ground water》2017,55(1):81-87

Recharge estimation is an important and challenging element of groundwater management and resource sustainability. Many recharge estimation methods have been developed with varying data requirements, applicable to different spatial and temporal scales. The variability and inherent uncertainty in recharge estimation motivates the recommended use of multiple methods to estimate and bound regional recharge estimates. Despite the inherent limitations of using daily gauged streamflow, recession curve displacement methods provide a convenient first‐order estimate as part of a multimethod hierarchical approach to estimate watershed‐scale annual recharge. The implementation of recession curve displacement recharge estimation in the United States Geologic Survey (USGS) RORA program relies on the subjective, operator‐specific selection of baseflow recession events to estimate a gauge‐specific recession index. This paper presents a parametric algorithm that objectively automates this tedious, subjective process, parameterizing and automating the implementation of recession curve displacement. Results using the algorithm reproduce regional estimates of groundwater recharge from the USGS Appalachian Valley and Piedmont Regional Aquifer‐System Analysis, with an average absolute error of less than 2%. The algorithm facilitates consistent, completely automated estimation of annual recharge that complements more rigorous data‐intensive techniques for recharge estimation.  相似文献   

Surficial sediment erodibility from time-series measurements of suspended sediment concentrations: development and validation     

Rooni Mathew  Johan C. Winterwerp 《Ocean Dynamics》2017,67(6):691-712

Numerical models of fine sediment transport depend on different approaches to parameterize the erosion properties of surficial sediment strata. These properties, namely the critical shear stress for erosion and the erosion rate coefficient, are crucial for reproducing the short-term and long-term sediment dynamics of the system. Methods to parameterize these properties involve either specialized laboratory measurements on sediment samples or optimization by model calibration. Based on observations of regular patterns in the variation of suspended sediment concentrations (SSC) over the tidal cycle in a small, narrow estuary, an alternate approach, referred to as the entrainment flux method, for quantifying the erosion properties of surficial bed strata is formulated and applied. The results of this method are shown to be analogous to the erosion data used to formulate the standard linear erosion formulation developed by various authors. The erosion properties inferred from the entrainment flux method are also compared to direct measurements of erodibility on sediment samples from the same site using the Gust microcosm apparatus. The favorable comparison of the two approaches suggests that the entrainment flux method can be used to infer and quantify the erodibility of surficial sediment strata in similar small and narrow estuaries. This method has certain advantages, chiefly its ease of implementation and the fact that it uses SSC time series which would typically be expected to be available for the study of or for model application at a given site. Guidelines for selecting the appropriate dataset for the application of the method are also presented.  相似文献