Author Archives: nanzt

A JoH paper on routing

Zhang L, Nan Z*, Liang X*, Xu Y, Hernandez F, Li L. Application of the MacCormack Scheme to Overland Flow Routing for High-spatial Resolution Distributed Hydrological Model. Journal of Hydrology. 2018, 558: 421-431.

Abstract:

Although process-based distributed hydrological models (PDHMs) are evolving rapidly over the last few decades, their extensive applications are still challenged by the computational expenses. This study attempted, for the first time, to apply the numerically efficient MacCormack algorithm to overland flow routing in a representative high-spatial resolution PDHM, i.e., distributed hydrology-soil-vegetation model (DHSVM), in order to improve its computational efficiency. The analytical verification indicates that both the semi and full versions of the MacCormack schemes exhibit robust numerical stability and are more computationally efficient than the conventional explicit linear scheme. The full-version outperforms the semi-version in terms of simulation accuracy when a same time step is adopted. The semi-MacCormack scheme was implemented into DHSVM (version 3.1.2) to solve the kinematic wave equations for overland flow routing. The performance and practicality of the enhanced DHSVM-MacCormack model were assessed by performing two groups of modeling experiments in the Mercer Creek watershed, a small urban catchment near Bellevue, Washington. The experiments show that DHSVM-MacCormack can considerably improve the computational efficiency without compromising the simulation accuracy of the original DHSVM model. More specifically, with the same computational environment and model settings, the computational time required by DHSVM-MacCormack can be reduced to several dozen minutes for a simulation period of three months (in contrast with one day and a half by the original DHSVM model) without noticeable sacrifice of the accuracy. The MacCormack scheme proves to be applicable to overland flow routing in DHSVM, which implies that it can be coupled into other PHDMs for watershed routing to either significantly improve their computational efficiency or to make the kinematic wave routing for high resolution modeling computational feasible.

Keywords: MacCormack Scheme; Overland Flow Routing; DHSVM; Kinematic Wave; Computational Efficiency

Links: Link1 (Elesvier, 50day’s free access since Feb 4, 2018) ; Baidu;

Captcha Decoder: pwntcha

在cygwin 2.9下重新编译了一下,不容易,遇到各种问题,主要还是代码太老了,库等都跟不上了。最后发现对我关心的事情还是没啥用,它适合的场合还是过于简单。把编译好的程序打包放在这里共享好了(链接在下文)。

pwntcha的主要说明网页在这里:http://caca.zoy.org/wiki/PWNtcha

几种常用的可以搞定的样式如下: Continue reading

DeltaCopy 在两个Windows机器上copy时文件权限问题

因为Cygwin迁移到ntfs时存在人文件权限问题,在win平台上会导致文件权限问题。rsync后每个文件和文件夹都被添上几个<not inherit>的用户及当前用户被deny掉。因此当前用户就无法访问虚拟目录对应的目录。

以下解决方法可以解决当前用户被deny的问题。但<not inherit>的用户仍然被添加。

  1. 在DeltaC端添加 –perms (两个英文短横线)
  2. DeltaC的Options里将 Change permissions on server to read/write 打上勾。

如果已经有部分目录已经被deny访问。采用以下方法:

  1. DeltaS的虚拟目录右击,选择fix file permission,如果文件多,需要耐心等待一些时间。
  2. 在上一级可以访问的目录上选择合适的权限,并将权限传播到下级文件和目录。文件多的时候,这个操作也会花一些时间。

Open Live Writer

微软Live Writer 2012无法在Win 10最新版本上安装了。

我一直使用Live Writer将博客贴上来,最近新买了一个Laptop Thinkpad X270,系统更新到最新的Win 10,在安装Live Writer 2012时提示无法安装了。遗憾了好一阵子。后来在微软Store里尝试搜索了一下,居然找到一个Open Live Writer,下载安装后,发现与Live Writer一般好用。大爱!

Image

Win 10屏幕字体放大显示模糊的问题

在100%字体显示是好的,但因为是1920×1080的分辨率,看起来太小,所以系统推荐是放大到125%,我放大到150%感觉合适。但放大后出现字体模糊的情况。此外当连接到第二块屏幕(1600×900),在这块屏幕上模糊的简直没法看。QQ、FSCapture等截图工具无法在第二块屏幕上使用。

在各大论坛都有讨论,没有好的解决方案。其中一个方案是,当连接到第2块时,将第2块选为主屏幕,用100%,这样可以部分解决第2块屏幕模糊的问题,但截图问题仍旧。类似问题2015年就有报告,到现在仍然没有解决好。Win 10真是越来越不给力。

偶然发现使用自定义放大(Custom Scaling)可以比较好解决上述问题:1 字体模糊;2 副屏模糊问题; 3 截图问题。但不管设置为125%,还是150%,显示的都是175%,估计又是一个Bug。见附图。

我使用的是Intel HD Graphics 620集成显示,驱动已经更新到最新。

Image

Windows 10启动时出现用户或密码错误的提示

更新到最新的Win10版本(10.0.16299 build 16299)后,在当地用户(Local User)登录时没有错误,切换到Microsoft帐户(邮件)时,重启出现“The user name or password is incorrect.”的错误提示,点击确定后,仍然可以使用指纹或PIN登录。而事实上用户帐号都没有问题。

网上有一些建议比如使用netplwiz关掉用户密码提示之类的,并不安全;使用Local帐号也可以避免。但这些方法仍然不适合连接到微软在线帐户的情况。我结合网上的提示,猜测是因为Local帐号与在线帐号密码不一致,在使用在线帐号登录前,Win 10错误的尝试Local帐号原密码登录(在切换为在线帐号后,Local帐号密码也被更改为相同的在线帐号密码),因此导致这个错误。

解决方法是在登录选项里的”在更新或重启后自动使用登录信息登录设备“(Use my sign-in info to automatically finish setting up my device after an update or restart)选择”关“(off)。

2017-11-16_124458