参数化模型中表示什么?(语义)-地球科学堆栈交换江南电子竞技平台江南体育网页版 最近30从www.hoelymoley.com 2023 - 07 - 10 - t09:00:45z //www.hoelymoley.com/feeds/question/8698 https://creativecommons.org/licenses/by-sa/4.0/rdf //www.hoelymoley.com/q/8698 3 参数化模型中表示什么?(语义) BarocliniCplusplus //www.hoelymoley.com/users/704 2016 - 09 - 07 - t15:33:22z 2016 - 09 - 08 - t14:27:10z < p >我知道WRF有许多不同的用途和选项,从大气化学与火灾使用,等等。代表一个参数化的什么?例如,在WRF-Chem,化学被认为是参数化?如果不是,区分从参数化机制?光解是参数化吗?< / p >生物排放参数化? //www.hoelymoley.com/questions/8698/-/8701 # 8701 6 由丹尼尔回答。heydebreck为参数化模型中表示什么?(语义) daniel.heydebreck //www.hoelymoley.com/users/5594 2016 - 09 - 08 - t08:23:47z 2016 - 09 - 08 - t14:27:10z < p >中定义的< a href = " http://glossary.ametsoc.org/wiki/Parameterization " > < / > AMS术语表,参数化是一种简化的一个或多个过程模型。一般我添加一个参数化模型中添加了一个错误,增加了不确定性的结果。在大多数情况下,参数化不是来源于物理定律,而是适合数据。< / p > < p >这些简化为不同的原因。你可能知道下面的例子,这个答案可能是短;-)但是我增加了他们对其他读者可能不会意识到它们的存在。< / p >

Parameterization due to spatial constraints

When we model meteorological and atmospheric chemistry processes in a certain domain, we split this domain into individual grid cells of a given size - such as grid cells of 10 km x 10 km size. Some atmospheric processes have a lower spatial extend than the grid cells - such as small scale turbulence and clouds smaller than 10 km. These things cannot be explicitly calculated by the model (except if we reduce the model resolution). Therefore, we approximate these things taking place on a spatial scale below 10 km. These approximations are denoted as parameterizations.

Parameterizations due to computing effort

When we consider processes such as particle formation, growth, and coagulation we could consider every particle or even every molecule in a model. However, in real world atmospheric applications we have too much particles than we could consider them individually. Therefore, we need to calculate the growth of particles on the base of some parameters and apply it on (log-normal) particle number/volume/... distributions.

Parameterizations due to missing and condensed information

Biogenic emissions are a nice example. We do not know exactly where which trees and plants are located (and which atmospheric conditions like humidity and temperature prevail). For some regions we know it: e.g. for the city of Hamburg there is a detailed (non-public) tree inventory existing. When we do not have this information and work in a gridded domain (i.e. 10 km x 10 km) we need to make a simplified assumption - such as 10% of the grid cell ground is covered by urban area, 30% by grassland, 10% by desert and 50% by forest (of which 70% are pine trees and 30% other trees). From this information and the average ground level temperature and humidity we need to estimate the amount of various emitted volatile organic compounds. Doing this, is a parameterizations because we over-simplify the actual real world.

But

From my feeling I would describe a process representation in a model as explicit/non-parameterized when it is included according to the best current/state-of-the-art knowledge. In contrast, when it is considerably simplified, I would denote it as a parameterization.

However, when we presented gas phase chemical processes by differential equations - like as it is done in the gas phase chemistry mechanisms of chemistry transport models -, I would not consider it as parameterizations because due to a large number of identical molecules (and the law of large numbers - probably) we do not actually introduce a large error.

Baidu
map