WRF Data Assimilation(同化)3D与4D的区别

sywyx

3D-Var和4D-Var均基于变分同化方法，在技术上有相同之处，也有很大区别。4D-Var克服了3D-Var在时间上不连续的缺点，具有变量的动力协调性，但计算量也随之增大。

The difference between three-dimensional (3D-Var) and four-dimensional (4D-Var) data assimilation is the use of a numerical forecast model in the latter.




WRF用户手册第6章是关于同化的，如果需要同化卫星等数据，还需要把4D装完。
手册上讲还有两个步骤：
(1) If you intend to run WRF 4D-Var, it is necessary to have WRFPLUS installed.

(2) To install WRFDA for the 4D-Var run:

>./configure 4dvar

>./compile all_wrfvar >& compile.out

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freekiller

3D和4D与同不同化卫星无关

盈星

资料同化，感觉就是高端。

刘振

4D同化就是3D同化加上时间维同化，期待你搞定了分享经验

sywyx

Prepare observational data for 3D-Var


Prepare observational data for 4D-Var


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Model is run with extra nudging terms for horizontal winds, temperature and water vapor
In analysis nudging, these terms nudge point-by-point to a 3d space-interpolated and time-interpolated analysis field
In obs-nudging, points near observations are nudged based on model error at obs site
The nudging is a relaxation term with a user-defined time scale around an hour or more
Nudging will work with nesting and restarts

sywyx

freekiller 发表于 2014-3-29 09:10
3D和4D与同不同化卫星无关

Note: WRFDA 4D-Var is able to assimilate conventional observational data, satellite radiance BUFR data, radar data, and precipitation data.

freekiller

sywyx 发表于 2014-4-2 09:31
Note: WRFDA 4D-Var is able to assimilate conventional observational data, satellite radiance BUFR  ...

这不是3D和4D的区别，3D当然可以同化这些。 这只是WRF4d才加的功能罢了

nplayer

3D和4D不就是纬度不同吗？或者是不是混合同化？

lee309

哪里可以下载用户手册？

lee309

同化与不同化到底区别有多大？