【转】水文模型相关_gldas水文模型

这里主要记录几个相关的水文模型学习情况。
（1）GLDAS-NOAH（Global Land Data Assimilation System (GLDAS)）
http://disc.sci.gsfc.nasa.gov/services/grads-gds/gldas

ftp://hydro1.sci.gsfc.nasa.gov/data/s4pa/GLDAS_V1/GLDAS_NOAH10_M

在这个网址可以下载到月数据，以grb后缀结束，同时一并的还有一个grb.xml索引文件，下载的时候需要一并。

The goal of the Global Land Data Assimilation System (GLDAS) is to ingest satellite and ground-based observational data products, using advanced land surface modeling and data assimilation techniques, in order to generate optimal fields of land surface states and fluxes。

Currently, GLDAS drives four land surface models (LSMs): Catchment, Noah, the Community Land Model (CLM), and the Variable Infiltration Capacity (VIC)。

GLDAS-2 has two components: one forced entirely with the Princeton meteorological forcing data (hereafter, GLDAS-2.0), and the other forced with a combination of model and observation based forcing datasets (hereafter, GLDAS-2.1). GLDAS-2.0 currently covers from 1948 to 2010 and will be extended to recent years as the dataset becomes available. GLDAS-2.1 covers from 2001 to present with about 1 month latency and will be updated monthly。

The GLDAS products are now available in the netCDF format, through a new, on-the-fly (OTF) GRIB-to-netCDF conversion service.

The Global Land Data Assimilation System (GLDAS) products are now available in the netCDF format. Users can now download the GLDAS products in netCDF format on-the-fly from the Mirador search and access tool. The converted netCDF files are compliant with the Climate and Forecast (CF) metadata convention. As an example, a user selects the monthly 1.0 degree CLM data set from the Mirador tool. A “NetCDF” button can then be clicked to download the file in netCDF format.

具体操作如下：

①在http://mirador.gsfc.nasa.gov/这个地方进行，搜索，比如以关键字“GLDAS Noah ”进行搜索，其中还有个时间跨度，time span 进行搜索，我们可以得到如下的结果：

然后根据自己的需求，进行选择第二个，Monthly，020版本的数据，再然后我们可以得到下面的页面：

点击Add All Files in All Pages To Cart，就可以将所有年份的数据都进行选择进去。然后我们可以在我们的购物车Cart里看到

通过下载工具wget进行下载，下载地址为http://ftp.gnu.org/gnu/wget/。

（1）将下载的软件，这里以wget-1.14为例，进行说明，将其放置在/usr/local/wget这个文件夹下面，当然建立这个文件夹的时候是需要权限的，需要sudo来完成；

（2）解压缩，sudo tar zxvf wget-1.14.tar.gz

（3）sudo cd wget-1.14

　　 sudo ./configure

（4）上个命令运行之后出现错误，configure: error: –with-ssl was given, but GNUTLS is not available.

（5）大概是需要安装GNUTLS，然后去网上进行下载ftp://ftp.gnupg.org/gcrypt/gnutls/，得到gnutls-3.1.5.tar.xz的一个文件，可以通过下面命令进行解压：

 sudo xz -d ***.tar.xz

 sudo tar -xvf  ***.tar
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可以看到这个压缩包是两层压缩，外面是xz压缩方式，里层是tar压缩方式。

（6）解压缩之后，通过sudo ./configure进行编译，结果又出现了问题， Libnettle 2.5 was not found. Note that you must compile nettle with gmp support.没办法，需要重新下载nettle2.5库，我们可以在 ftp://ftp.gnu.org/gnu/nettle进行选择下载。然后通过tar进行解压缩，通过./configure完成相关配置，这次比较成功的运行了，然后sudo make，出现了一些状况：

root@jeydragon-VirtualBox:/usr/local/wget/nettle-2.5# make

make all-here

make[1]: Entering directory `/usr/local/wget/nettle-2.5’

m4 ./asm.m4 machine.m4 config.m4 \

aes-decrypt-internal.asm >aes-decrypt-internal.s

/bin/sh: m4: not found

make[1]: * [aes-decrypt-internal.o] Error 127

make[1]: Leaving directory `/usr/local/wget/nettle-2.5’

make: * [all] Error 2

大概问题就是m4没有安装，然后apt-get install m4，这下就可以编译make以及安装make install通过了，很神奇。

（7）重启linux一次，问题依旧，Libnettle 2.5 was not found. Note that you must compile nettle with gmp support.快泄气了。大概是后半句有问题，网上查找说The library depends on libnettle and p11-kit.然后去http://p11-glue.freedesktop.org/releases/下载p11-kit,./configure,make,sudo make install.安装成功

（8）去http://gmplib.org/下载gmp，大概1.6M大小，然后./configure,make,sudo make install.安装成功。

（9） cd nettle-2.4

   make clean #必须!然后再make，make install，终于是几经周折与曲折，安装成功了，切记make clean这一步；
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（10）然后重新进去wget这个文件夹下面，./configure,make,sudo make install.安装成功。

（11）wget –content-disposition -i myfile.dat可以下载相关文件。

     --content-disposition：试验性的支持Content-Disposition头


 --content-disposition   honor the Content-Disposition header when

                           choosing local file names (EXPERIMENTAL).
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终于的终于，到此为止可以将数据进行正确的下载到本地，忍不住的称赞一下自己，Good Job, Well Done!

The temporal resolution for the GLDAS-2 products is 3-hourly. Monthly products are also generated through temporal averaging of the 3-hourly products. Output files from Noah model are briefly described here.

File Naming Convention

GLDAS-2 data are named in accordance with the following convention:

GLDAS_.A...grb

可以看出这次下载的gldas1的数据。

The table below shows the GRIB Product Definition Section (PDS) ID, the corresponding parameter name, the units, the time information, and the indication of Forcing parameters. The GLDAS data set includes predicted fields from the land surface models as well as input meteorological fields that were used as forcing.

Reading the Data

WGRIB, GrADS, or other GRIB readers are required for reading the GLDAS data.

WGRIB is a program to manipulate, inventory, and decode GRIB files. The source co

and installation instructions for WGRIB are available from

http://www.cpc.ncep.noaa.gov/products/wesley/wgrib.html

Wgrib_Download

下面尝试通过WGRIB来完成grb文件的读取。

①这个貌似在linux下面通过命令sudo apt-get install grads然后就可以自动安装
②安装成功之后，输入wgrib + 文件名 就可以得到该文件的相关信息
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其代表的意思如下：

可以看出共28个变量，具体如下：

这里大概需要提取出框框中这四个数据，然后将其合并，大概可以得到土壤水的含量。对于netCDF文件似乎也是可以通过Grads进行操作。