Geoscience Reference
In-Depth Information
Assessment of the credibility that specified land-atmosphere coupling mechanisms act to influence weather and climate made on the basis of
physical plausibility and the availability of observational and modeling evidence (overviewed in the text) together with an assessment of the current level of
understanding of each mechanism and present day ability to represent it in models.
Table 25.1
Quantification
and modeling
of influence
(Good, Medium,
or Poor)
Plausible
physical basis
for the influence
Observational
evidence for
the influence
Modeling
evidence
for the influence
Credibility
of influential
mechanism*
Land-surface influence on climate
or weather
A. Influence of existing
land-atmosphere interactions
1. Influence of topography
Yes
Yes
Yes
Extremely likely
Long-term: Medium
2. Contribution to atmospheric water
availability
(“recycling”)
Yes
Yes
Yes
Extremely likely
Short-term: Poor
Medium
B. Influence of transient changes
in land surfaces
1. Transient changes in soil moisture:
Yes
Yes
Yes
Extremely likely
Medium
a. Regional scale influence on climate
Yes
Yes
Yes
Likely
Medium
b. Mesoscale influence on weather
2. Transient changes in vegetation
Yes
Yes
Yes
Extremely likely
Medium
3. Transient changes in frozen precipitation
cover
Yes
Yes
Yes
Extremely likely
Medium
(Note: in practice these influences
are strongly coupled)
C. Influence of imposed changes
in land cover
1. Local effect on 2 m climate
Yes
Yes
Yes
Extremely likely
Good
2. Effect of regional-scale changes
in land cover
Yes
Some
Yes
Very likely
Medium
3. Effect of imposed land-cover
heterogeneity
Ye s
Ye s
Ye s
Extremely likely
Medium
* Extremely likely > 95%; Very likely > 90%; Likely > 66%; More likely than not > 50%; Unlikely < 33%; Very Unlikely < 10%; Extremely unlikely < 5%
