The characteristics of sea fog with different airflow over the Huanghai Sea in boreal spring

Using the observations from ICOADS datasets and contemporaneous NCEP/NCAR reanalysis datasets during 1960-2002,the study classifies the airflows in favor of sea fog over the Huanghai （Yellow） Sea in boreal spring （April-May） with the method of trajectory analysis,and analyzes the changes of proportions of warm and cold sea fogs along different paths of airflow.According to the heat balance equation,we investigate the relationships between the marine meteorological conditions and the proportion of warm and cold sea fog along different airflow paths.The major results are summarized as follows.（1） Sea fogs over the Huanghai Sea in spring are not only warm fog but also cold fog.The proportion of warm fog only accounts for 44% in April,while increases as high as 57% in May.（2） Four primary airflow paths leading to spring sea fog are identified.They are originated from the northwest,east,southeast and southwest of the Huanghai Sea,respectively.The occurrence ratios of the warm sea fog along the east and southeast airflow paths are high of 55% and 70%,while these along the southwest and northwest airflow paths are merely 17.9% and 50%.（3） The key physical processes governing the warm/cold sea fog are heat advection transport,longwave radiation cooling at fog top,solar shortwave warming and latent heat flux between airsea interfaces.（4） The characteristics of sea fog along the four airflow paths relate closely to the conditions of water vapor advection,and the vertical distribution of relative humidity.

Numerical Simulation of Moisture Movement in Unsaturated Expansive Soil Slope Suffering Permeation

This study develops a way of analyzing moisture movement in unsaturated expansive soil slope. The basic equations and the integrated finite difference method for moisture movement in unsaturated soils are briefly described, and the calculation code MFUS2 has been developed. The moisture movements in unsaturated expansive soil slopes suffering precipitation were simulated numerically. The simulation results show that expansion or contraction must be taken into account in an analysis model. A simplified equivalent model for calculating rainwater infiltration into expansive soil slopes has been developed. The simplified equivalent model divides the soil slope into two layers according to the extent of weathering of the soil mass at depth. Layer Ⅰ is intensively weathered and moisture can be fully evaporated or rapidly absorbed. The moisture movement parameters take into account the greater soil permeability caused by fissures. Layer Ⅱ is unweathered and the soil is basically undisturbed. The moisture movement parameters of homogeneous soils are applicable. The moisture movements in unsaturated ex- pansive soil slopes suffering precipitation were simulated numerically using the simplified equivalent model. The simulation results show that the moisture movement in the expansive soil slope under rainfall permeation mainly takes place in the extensively weathered layer Ⅰ which closely simulates the real situation.

Water Leakages in Public Water Supply System and How to Prevent Them

The article addresses the results of effective water losses prevention in public water supply systems, focusing on procedures for monitoring hidden leaks as the main part of losses and as the first step to control and prevent them. The described methodology has been applied based on a cross-border cooperation between twin capital cities Vienna and Bratislava in the Central Europe Region within the project deWaloP （Developing Water Loss Prevention） and adopted in Bratislava Water Company （BVS） in the Slovak Republic. The paper provides a complex of simple and easily available practices for analyses of water distribution measurements bringing essential information as to the necessity to use advanced procedures to actively reduce leakage. These practices involve minimum night flows analyses, hydrodynamic pressures analyses, pinpointing of water leakages by working with valves in the water network, the methodology of setting alarm limits for measured data, as well as use of advanced practices to obtain missing topologic data. As the water infrastructure in former socialistic countries are in bad technical condition and the lack of pertinent operational data is a significant obstacle to the application of a more sophisticated methodology based on GIS and other information systems, the procedures focus on using the most simple way to evaluate and control water losses. Finally, the introduction of described methodology in Bratislava Water Company after many years of unsuccessful effort even with expensive sophisticated leakage equipment brought positive outputs and the graph line of water losses level is finally going down. The use of expensive multi-correlating equipment together with human resources on the basis of implementing the above described leakage monitoring will subsequently become more effective, as it shall pinpoint major leakages, disclosure and removal of that shall significantly contribute to the effective reduction of water losses.

Empowering Conditions for Good Water Governance-a Sustainable Model： Vilanculos Case Study （Mozambique）

This article shows the results of the project Empowering conditions for good water governance-a sustainable model： Vilanculos case study （Mozambique）, co-financed by the European Community. This project had the aim of improving sanitary conditions and increasing economic and financial sustainability of water services for the population of Vilanculos. The project has been developed and deployed with cooperation between Acque del Chiampo （an Italian water utility, near Vicenza）, the University of Brescia and the Vilanculos public water service utility, Empresa Mo^ambicana de Agua （EMA）. The paper reports analytical praxis for water distribution measurements, capable of providing essential data about the water network performances, to assess the eventual need for actions in order to solve possible and effective problems of the water service. These practices involve flow and pressure analyses, pinpointing of the network＇s criticalities and leakages by in-situ inspections along the network, managing the valves together with water service utility, as well as the use of a water distribution model to simulate the effects of the proposed interventions and specific software to automatically register bills and payments.

Effects of the buried straw layer on soil water and nitrogen distribution under different irrigation limits

At present,water and fertilizer use efficiency is low in many cultivation areas in southern China.Studies show that the buried straw layer can effectively conserve water and fertilizer.To investigate the optimal irrigation upper limit above the straw barrier and its effect on soil moisture and nitrogen distribution,an indoor soil column experiment was conducted.Six treatments were designed consisting of two levels of straw layer i.e.,(with and without buried straw layer at 25 cm depth),and three irrigation water upper limits i.e.,(saturated moisture content(s),field water holding capacity(f),and 80%of field water holding capacity(0.8f)as the upper limit of irrigation).The result revealed that the buried straw layer can inhibit water infiltration and significantly increase the water storage capacity and water storage efficiency of 0-25 cm soil depth.Under the condition of no evaporation,when the upper limit of irrigation water does not exceed the field water holding capacity,the storage efficiency of 0-25 cm soil water reaches 89%-91%after 6 d.Moreover,a buried straw layer can inhibit the deep percolation of nitrate nitrogen and increase the amount of nitrate-nitrogen in 0-25 cm soil.The 80%field water holding capacity irrigation upper limit combined with straw interlayer treatment had a higher nitrate-nitrogen content in the 0-25 cm soil layer than other treatments.Therefore,80%of field water holding capacity as the upper limit of irrigation combined with buried straw layer is the optimal strategy to conserve soil water and nitrogen in the upper soil profile.