Remote sensing in hydrology   总被引：4，自引：0，他引：4  

Thomas J. Schmugge  William P. Kustas  Jerry C. Ritchie  Thomas J. Jackson  Al Rango 《Advances in water resources》2002,25(8-12)

Remote sensing provides a means of observing hydrological state variables over large areas. The ones which we will consider in this paper are land surface temperature from thermal infrared data, surface soil moisture from passive microwave data, snow cover using both visible and microwave data, water quality using visible and near-infrared data and estimating landscape surface roughness using lidar. Methods for estimating the hydrometeorlogical fluxes, evapotranspiration and snowmelt runoff, using these state variables are also described.  相似文献   

Planar Gardner solitons and double layers in dusty electronegative plasmas with kappa distributed electrons     

T. Akhter  M. M. Hossain  A. A. Mamun 《Astrophysics and Space Science》2013,345(2):283-290

A theoretical investigation has been made on the Dust ion-acoustic (DIA) Gardner solitons (GSs) and double layers (DLs) in electronegative plasma consisting of inertial positive and negative ions, super-thermal (kappa distributed) electrons, and negatively charged static dust. The standard reductive perturbation method is employed to derive the Korteweg-de Vries (K-dV), modified K-dV (mK-dV), and standard Gardner equations, which admits solitary waves (SWs) and DLs solutions. It have been found that GSs and DLs exist for α around its critical value α _c , where α _c is the value of α corresponding to the vanishing of the nonlinear coefficient of the K-dV equation. The parametric regimes for the existence of both the positive as well as negative SWs and negative DLs are obtained. The basic features of DIA SWs and DLs are analyzed and it has been found that the polarity, speed, height, thickness of such DIA SWs and DLs structures, are significantly modified due to the presence of two types of ions and spectral index (κ) of super-thermal electrons. It has also been found that the characteristics of DIA GSs and DLs, are different from that of the K-dV solitons and mK-dV solitons. The relevance of our results to different interstellar space plasma situations are discussed.  相似文献   

Where do the progenitors of millisecond pulsars come from?     

A. Taani  C.M. Zhang  M. Al‐Wardat  Y.H. Zhao 《Astronomische Nachrichten》2012,333(1):53-59

Observations of a large population of millisecond pulsars (MSPs) show a wide divergence in the orbital periods (from approximately hours to a few months). In the standard view, low‐mass X‐ray binaries (LMXBs) are considered as progenitors for some MSPs during the recycling process. We present a systematic study that combines different types of compact objects in binaries such as cataclysmic variables (CVs), LMXBs, and MSPs. We plot them together in the so called Corbet diagram. Larger and different samples are needed to better constrain the result as a function of the environment and formations. A scale diagram showing the distribution of MSPs for different orbital periods and the aspects for their progenitors relying on accretion induced collapse (AIC) of white dwarfs in binaries. Thus massive CVs (M ≥ 1.1 M_⊙) can play a vital role on binary evolution, as well as of the physical processes involved in the formation and evolution of neutron stars and their magnetic fields, and could turn into binary MSPs with different scales of orbital periods; this effect can be explained by the AIC process. This scenario also suggests that some fraction of isolated MSPs in the Galactic disk could be formed through the same channel, forming the contribution of some CVs to the single‐degenerate progenitors of Type Ia supernova. Furthermore, we have refined the statistical distribution and evolution by using updated data. This implies that the significant studies of compact objects in binary systems can benefit from the Corbet diagram.Observations of a large population of millisecond pulsars (MSPs) show a wide divergence in the orbital periods (from approximately hours to a few months). In the standard view, low‐mass X‐ray binaries (LMXBs) are considered as progenitors for some MSPs during the recycling process. We present a systematic study that combines different types of compact objects in binaries such as cataclysmic variables (CVs), LMXBs, and MSPs. We plot them together in the so called Corbet diagram. Larger and different samples are needed to better constrain the result as a function of the environment and formations. A scale diagram showing the distribution of MSPs for different orbital periods and the aspects for their progenitors re  相似文献   

Electrostatic solitary structures in a four-component adiabatic dusty plasma     

S. Tasnim  A. Mannan  A. A. Mamun 《Astrophysics and Space Science》2012,337(1):261-267

A theoretical investigation has been made of propagating electrostatic waves in a four-component adiabatic dusty plasma, whose constituents are adiabatic electrons, adiabatic ions, adiabatic positively and as well as negatively charged warm dust. The basic features of the solitary structures in such a four-component adiabatic dusty plasma are studied by the reductive perturbation method. It is found that the presence of the positive dust component does not only significantly modify the basic properties of the solitary waves, but also causes the existence of the positive solitary potential structures, which is an interesting feature shown in an adiabatic dusty plasma with the dust of opposite polarity. It is also observed that the basic properties (polarity, speed, amplitude and width) of the DA SWs are significantly modified by the effects of adiabaticity (γ>1) of electrons, ions, negatively as well as positively charged warm dust. The present investigation can be of relevance to the electrostatic solitary structures observed in various dusty space plasma environments (viz. cometary tails, upper mesosphere, Jupiter’s magnetosphere, etc.).  相似文献   

Food and the city: urban agriculture and the new food revolution     

Md Rajibul Al Mamun 《Urban geography》2013,34(1):152-153

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Hydrogeological condition and assessment of groundwater resource using visual modflow modeling,Rajshahi city aquifer,Bangladesh     

M. Al Mamunul Haque  C. S. Jahan  Q. H. Mazumder  S. M. S. Nawaz  G. C. Mirdha  P. Mamud  M. I. Adham 《Journal of the Geological Society of India》2012,79(1):77-84

The Rajshahi city is the fourth largest metropolitan city in Bangladesh on the bank of the River Padma (Ganges). Here an upper semi-impervious layer overlies aquifer — the source for large-scale groundwater development. The groundwater resource study using Visual MODFLOW modeling shows that recharge occurs mainly due to infiltration of rainfall and urban return flow at low rate, and water level fluctuates seasonally in response to recharge and discharge. Hydraulic connection between river and aquifer which indicates inflow from high river water levels beyond its boundaries. The total groundwater abstraction in 2004 (15000 million liters) is lower than total input to aquifer reveals an ample potentiality for groundwater development with increasing demand. But groundwater shortage (1000 million liter/year) especially in the vicinity of the River Padma in dry season happens due to its increasing use and fall of river water level resulting in reduced inflows and hence decline in groundwater level. The conjunctive use of surface water-groundwater and its economic use will help for sustainable groundwater supply to avoid adverse impact.  相似文献   

GEOLOGY AND STRUCTURAL CONTROLS ON SOME OF REE AND POLYMETALIC Nb-Zr-Ta DEPOSITS-BEARING ALKALINE-PERALKALINE ROCKS IN THE ARABIAN SHIELD, KINGDOM OF SAUDI ARABIA     

Maher A. El Amawy  Ghazi A. Kattu  Hassan M. Al Marzouki 《《地质学报》英文版》2013,87(Z1):750-751

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The Australian-Antarctic segment of Gondwana     

Al. A. Schreider  A. A. Schreider  G. L. Kashintsev 《Oceanology》2012,52(3):422-435

Australia is one of the major continental terranes in Gondwana’s structure. At the same time, the precise position of Australia in this structure has not yet been clearly identified. According to different works, Australia is connected to Antarctica in a number of areas near Wilkes Land, Adelie Land, and Victoria Land. The comprehensive analysis of the geological and geophysical data allows us to reconstruct the optimal relative position of the continents and to reach a conclusion about the propagation of the tectonic structures of Australia towards Antarctica.  相似文献   

Water Purification Using Cost Effective Material Prepared from Agricultural Waste: Kinetics,Isotherms, and Thermodynamic Studies          下载免费PDF全文

Mu. Naushad  Mohammad Rizwan Khan  Zeid Abdullah ALOthman  Ala'a H. Al‐Muhtaseb  Md. Rabiul Awual  Ayoub Abdullah Alqadami 《洁净——土壤、空气、水》2016,44(8):1036-1045

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Three-phase measurements of oil and gas trapping in sand packs     

Saleh K. Al Mansoori  Stefan IglauerChristopher H. Pentland  Martin J. Blunt 《Advances in water resources》2009

We measure the trapped saturations of oil and gas as a function of initial saturation in water-wet sand packs. We start with a water-saturated column and inject octane (oil), while water and oil are produced from the bottom. Once water production has ceased, air (gas) then enters from the top, allowing oil and gas to drain under gravity for different times. Finally water is then injected from the bottom to trap both oil and gas. The columns are sliced and the fluids analyzed using gas chromatography. We find that for high initial gas saturations more gas can be trapped in the presence of oil than in a two-phase (gas/water) system. The residual gas saturation can be over 20% compared to 14% in two-phase flow [Al Mansoori SK, Iglauer S, Pentland CH, Bijeljic B, Blunt MJ. Measurements of non-wetting phase trapping applied to carbon dioxide storage. Energy Procedia 2009;1(1):3173–80]. This is unlike previous measurements on consolidated media, where the trapped gas saturation is either similar or lower to that reached in an equivalent two-phase experiment. For lower initial gas saturation, the amount of trapping follows the initial-residual trend seen in two-phase experiments. The amount of oil trapped is insensitive to initial gas saturation or the amount of gas that is trapped, again in contrast to measurements on consolidated media. More oil is trapped than would be predicted from an equivalent two-phase (oil/water) system, although the trapped saturation is never larger than the maximum reached in two-phase flow (around 11%) [Pentland CH, Al Mansoori SK, Iglauer S, Bijeljic B, Blunt MJ. Measurement of non-wetting phase trapping in sand packs. In: SPE 115697, proceedings of the SPE annual technical conference and exhibition, Denver, Colorado, USA; 21–24 September 2008]. These initially surprising results are explained in the context of oil layer stability and the competition between snap-off and piston-like advance. In two-phase systems, displacement is principally by cooperative piston-like advance with relatively little trapping, whereas in consolidated media snap-off is generally more significant. However, oil layer collapse events during three-phase waterflooding rapidly trap the oil which acts as a barrier to direct water/gas displacement, except by snap-off, leading to enhanced gas trapping.  相似文献