## Simple Diagnostic Biosphere Model (SDBM)

The model is based on the approach of Monteith[ 1972, 1977] and Kumar and Monteith [ 1981].It considers in stantaneous NPP (called P in the formulae) as a fraction of the incoming solar energy stored in to organic dry matter.

carbon cycle data assimilationterrestrial biosphereuncertainty analysis
167

#### Authorship

Authorship is unclear, you can claim the item.

#### Classification(s)

Method-focused categoriesProcess-perspectivePhysical process calculation
Method-focused categoriesProcess-perspectiveBiological process calculation

#### Model Description

English {{currentDetailLanguage}} English

In brief,the model calculates a pure seasonal cycle of net biosphere–atmosphere fluxes as the difference of two fluxes inany month at each land grid cell,

F = H - NPP

where F is the net flux to the atmosphere, H is the heterotrophic respiration, and NPP is the net primary productivity.

The calculation is performed on the basis of measured Normalized Differential Vegetation Index (NDVI), incoming solar radiation, and surface temperature. There is an additional time-dependent water-stress term a, which may limit the efficiency either of NPP, or heterotrophic respiration, or both. This factor will be included in various of the calculations in this work in either of the two fluxes H and NPP; in the case described below, it is included in both.

NPP is calculated for each month as

where APAR is absorbed photosynthetically active radiation and is a light-use efficiency parameter. APAR is computed from NDVI data by Gallow [1992] and incoming solar radiation inferred from cloudiness data by Leemans and Cramer [1991] using the method of Linacre [1968].

Heterotrophic respiration H is calculated as an exponential function of temperature as

where is the heterotrophic respiration rate at T = 0 and  (i.e., no water stress) and Q10 is the ratio of respiration at T + 10 to that at T; T is given in °C. We have absorbed into the formulation of H for later convenience.

In order to ensure a balanced biosphere (no net annual flux), we rescale H0 at each grid cell so that integrated NPP and H are equal over a year. Thus H0 is not a free parameter.

The water-stress factor, a = AET/PET (actual divided by potential evapotranspiration), is computed with the model of Prentice et al. [1993]. PET is assumed equal to equilibrium evapotranspiration, and AET is the minimum of PET and a supply rate assumed proportional to soil moisture. The model neglects the effect of soil freezing and snow accumulation, so that at low ambient temperatures where PET is mostly small, a tends toward 1. Freezing-induced drought effects are therefore not considered in SDBM; low temperatures rather affect H through its temperature dependence given by the value of Q10.

We can now write the total flux as

Subject to the constraint that

where integrals are taken over the annual cycle. Integrals are calculated as sums of monthly values weighted by the length of the month.

#### How to Cite

Zhiyi Zhu (2019). Simple Diagnostic Biosphere Model (SDBM), Model Item, OpenGMS, https://geomodeling.njnu.edu.cn/modelItem/7882aef5-568d-4b1a-811b-86cae1cf0557

#### Authorship

Authorship is unclear, you can claim the item.

#### QR Code

• {{curRelation.name}}
{{curRelation.name}}

{{curRelation.overview}}
{{curRelation.author.join('; ')}}
{{curRelation.journal}}

Related Items
{{props.row.name}}

You can link resource from repository to this model item, or you can create a new {{typeName.toLowerCase()}}.

{{ props.row.description }}
{{ props.row.description }}
Drop the file here, orclick to upload.
File size should not exceed 10m.
Select From My Space

These authorship information will be submitted to the contributor to review.

Cancel Submit
Cancel Submit
{{ item.label }} {{ item.value }}
{{props.row.localName}}
Model Name :
Cancel Submit Cancel Submit
Name:
Version:
Model Type:
Model Domain:
Scale:
Purpose:
Principles:
Incorporated models:

Model part of

larger framework

Process:
Information:
Initialization:
Hardware Requirements:
Software Requirements:
Inputs:
Outputs:
Cancel Submit
Title Author Date Journal Volume(Issue) Pages Links Doi Operation
Cancel Submit

Yes, this is it Cancel

OK
Cancel Confirm
Model Classifications 1
Model Classifications 2
Title Author Date Journal Volume(Issue) Pages Links Doi Operation

#### NEW

Name:
Affiliation:
Email:
Homepage:

Yes, this is it Cancel

Confirm
path
:
/{{path.name}}
search results of '{{searchContentShown}}'

#### No content to show

{{item.name}}

.

{{item.suffix}}

.{{item.suffix}}

Max: {{toDecimal1(capacity/1073741824)}} GB
Copy
Delete
Rename
/{{path.label}}
Change
/{{path.name}}
Select File
Cancel Confirm
path
:
/{{path.name}}
/..
Cancel Confirm
{{ data.name }}
##### You have select  {{multipleSelection.length+multipleSelectionMyData.length}} data .
• Output Data
• {{item.computableName}}@{{formatDate(item.runTime)}}
{{scope.row.type}}
{{ scope.row.tag }}
• Fork Data
{{it.category}}

#### NEW

Name:
Affiliation:
Email:
Homepage:
previous next conform
Model Classifications

You can link related {{relateItemType}} from repository to this model item, or you can create a new {{relateItemType.toLowerCase()}}.

Related Items
{{ props.row.description }}
{{ props.row.description }}
Cancel OK