变化环境下渭河流域水资源演变规律分析

渭河是黄河最大的支流，它是黄河中下游主要洪水来源区之一，也是黄河主要的产沙区之一。伴随气候变化、人类对水资源的开发利用活动加剧、大规模水土保持工程建设以及其他人类活动影响．渭河流域水资源的演变规律发生很大的变化。本文基于水资源二元演化模型研究了渭河流域的水资源演变规律，分析的水资源演变规律不仅包括狭义水资源。还包括广义水资源。本文所指的狭义水资源就是传统的水资源，即地表、地下水资源；广义水资源不仅包括狭义水资源，还包括直接为人类和生态系统所利用的降水。对1956-2000年渭河流域水资源演变过程进行了模拟．模拟结果表明．主要受降水减少和人类活动影响，1980-2000年地表水资源比1956-1979年衰减了7.3％，不重复地下水资源增加了20．2％．狭义水资源量减少了2．1％，直接为人类和生态系统所利用的降水减少了1．9％，广义水资源减少2．0％。考虑社会经济用水变化和土地利用变化，本文还预测了2020年水资源的演变趋势。经预测，2020年地表水资源量为81．6亿m63,比2000年少3．20亿m^3；不重复地下水资源量为24．62亿m^3，比2000年少0．28亿m^3；狭义水资源总量为106．21亿m^3，比2000年少3．48亿m^3；直接为人类和生态系统所利用的降水为487．16亿m^3，比2000年多3．05亿m^3；广义水资源量为593．37亿m^3，比2000年少0．43亿m^3。

浑河流域水资源演变规律研究

浑河流域水资源演变规律受人类大规模水土保持工程建设、水资源开发利用活动加剧、气候变化和其它活动影响,已发生明显改变。文章运用二元演化模型分析了浑河流域地下水、地表水、直接为生态环境以及人类利用的降水等水资源演变规律,模拟浑河流域1976-2020年水资源演变过程。结果表明:浑河流域水资源受降雨量减少、人类水资源不合理开发利用等因素影响呈减少趋势,对浑河流域应加强最严格水资源管理,实现高效可持续利用。

变化环境下大凌河流域水资源演变规律分析

文章运用二元水循环理论建立了分布式水文预测模型,研究了大凌河流域广义和狭义水资源在变化环境下的演变规律。运用预测模型对大凌河流域在1971~2014年水资源历史演变规律进行模拟,对该流域在2030年的水资源演变趋势进行预测分析。结果表明人类对水资源的不合理开发利用以及降雨量减少是引起水资源减少的主要因素,未来大凌河流域水资源继续减少,目前应加强对大凌河流域水资源的管理和控制,合理开采利用水资源。

Test of a low-mass contact binary model by comparing the relations obtained from theory with those from observations

The W UMa-type contact binaries have been observed for several decades.To construct the evolutionary model for W UMa-type contact binaries,many difficulties were encountered due to the existence of complicated physical processes in such systems.The model introduced by Huang,Song and Bi includes some special and unique understandings of the physical processes of contact binaries.It is necessary to test whether this model can be used for W UMa-type contact binaries.The best way to test a theoretical model is to know whether this model can explain the observational phenomena of such systems.For this aim,a comparison is performed for the relations of mass-luminosity,mass-radius,and the distribution in the HR diagram obtained from the model introduced by Huang et al.and those from the astronomical observations.The result of the comparison indicates that this model can be applied to W UMa-type contact binaries and can explain the observational phenomena of such binaries.

Contact binaries:Ⅱ.The importance of deformation caused by rotation and tides to the light curve of a contact binary

The theoretical light curves of contact binaries are calculated with and without putting in the contact binary evolution model.Firstly,we do not use the contact binary evolution model.A comparison of the light curve is performed with and without the deformation caused by rotation and tides.It shows that the light curve presents many differences,especially on the bottom and top.Secondly,we adopt the contact binary model [Huang R Q,et al.Chin J Astron Astrophys,2007,7:235-244;Song H F,et al.Chin J Astron Astrophys,2007,7:539-550] and compute the theoretical light curve with and without rotational and tidal effects by studying three binary systems(with low-,intermediate-and high-mass components).The bottom and top of the theoretical light curves are discussed and compared to observations.The results show that taking into account the rotational effect has a better agreement with observations than without it.Therefore,the deformation of the light curve of contact binaries caused by rotation and tides is very important.Meanwhile,the rotational and tidal effect can advance the start of the semi-detached,contact phase and the time of mass-reversal.