[1] We present estimates of nitrogen (N) inputs to the Changjiang River basin for the period 1968–1997. The total N input is approximately 7.8 10 kg in 1997, which is a threefold increase over 1968 levels. N fixation was often a dominant input before 1978, providing about 2.2 10 kg year , while N fertilizer dominated N input after 1983, supplying an additional input of some 4.4 10 kg year . Mor...

The prerequisite of maintaining an efficient and safe mining operation is the proper design of a mine by considering all aspects. The first step in a coal mine design is a realistic geometrical modelling of the coal seam(s). The structural features such as faults and folding must be reliably implemented in 3D seam models. Upon having a consistent seam model, the attributes such as calorific val...

gully erosion is one of the most complicated and destructive forms of water erosion. in order to prevent this erosion, the important factors advancing gully head must be recognized. nowadays, several models have been proposed in measuring gully head advancement and identifying the severity of erosion. these models must be calibrated for each country to see whether they are applicable or not. so...

First posted January 24, 2023 For additional information, contact: Director, Upper Midwest Water Science Center U.S. Geological Survey1 Gifford Pinchot Drive Madison, WI 53726Contact Pubs Warehouse Flood frequency characteristics and estimated flood discharges for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, 0.2-percent annual exceedance probabilities were computed at 299 streamgaged locations in Wisco...

Recent evidence for nonlinear behavior of strong motions generated by the Northridge, California, earthquake relies explicitly on the analysis of aftershock data. Thus, correcting these observations for propagational and source effects becomes a crucial step in these studies. Here, we demonstrate that the dipping structure near the edges of the San Fernando Valley can strongly alter the local s...

We present a framework to characterize terrestrial functions—surficial and bottom topographic regions that are represented, respectively, as raster digital elevation models DEMs and digital bathymetric models DBMs —through analysis of flow fields that are simulated via geodesic morphology. Characterization of such functions is done via a new descriptor. Computation of this new descriptor involv...

nowadays, a noticeable part of the relations among the states turn around the environment protection. therefore, the right for ever-creasing use of the existing resources of this inland sea cannot be exclusive to any caspian state and the aftermath involves all countries of this basin. in this respect, agreement on political border and boundaries with the caspian sea?s ecosystem is a difficult ...

S U M M A R Y We use a numerical simulation to investigate the response of sediment-filled valleys to P-SV seismic excitation. The calculation is carried out using the discrete wavenumber-boundary integral equation method. We study in particular the case of explosion sources located within a basin or in its vicinity. We show that large amplification or defocusing effects are related to the sour...

[1] Understanding the processes driving the carbon cycle in the Arctic Ocean is important for assessing the impacts of the predicted rapid and amplified climate change in this region. We analyzed settling particle samples intercepted by a time-series sediment trap deployed in the abyssal Canada Basin (at 3067 m) in order to examine carbon export to the deep Arctic Ocean. Strikingly old radiocar...