100
diurnally averaged data, therefore the bucket approximation is mostly used in AMs which
do not include the diurnal cycle of insolation.
Some of these simple parameterizat ions of t he surface energy and water budgets were
sufficient to provide first order surface forcings for early climate models. However, starting in the early eighties, the need for more comprehensive biophysical models of surface
processes was recognized for a more realistic description of biosphere-atmosphere interactions. The first biophysically-based ESEMs were developed in the mid-eighties and, since
then, such type of surface process schemes have been widely used in climate models. The
characteristics of state-of-the-art, biophysically-based ESEMs available in the literature
are discussed in the next sections.
3.2. State of the art ESEMs
To date over 30 surface process models have been developed. However, they are in
some ways mostly based on two pioneering schemes, the Biosphere-Atmosphere-Transfer
Scheme (BATS) of Dickinson et al. (1986, 1993) and the Simple Biosphere model (SiB) of
Sellers et al. (1986). Figure 4 illustrates the basic sub-components of most state-of-theart ESEMs: i) A soil model ; ii ) A vegetation model; iii) a snow model; and iv ) a surface
runoff model. These su b-components, which are coupled through exchanges of energy and
water at their interfaces, are described in the next sub-sections.
SENSIBLE
EXCHANGE
A.''Dcly"amlc:
f.s.I.'arM:.
(r.J
Lui drlo
, I /
-0/
. ,
RAOIA TlVE EXCHANGE
MOISTURE
EXCHANGE
----T.--~----~L--,rf~~~~~~~-+~~~~ .
Low.' .01
lel'/'lOeralur.
T ..
1.100'" 101
•• ,.., Cd,,)
tEs:S::':::;;--r - r t
FIIocll,,; dl'lolrlt.ulIOf1 tahO
Is fl,ll'tC, . . 01 ¥'eoe'all'On If~
.011
column (4.)
- , ' ---' ·-1
Figure 4 Schematic representation of a state-of-the-art ESEM (BATS).
diurnally averaged data, therefore the bucket approximation is mostly used in AMs which
do not include the diurnal cycle of insolation.
Some of these simple parameterizat ions of t he surface energy and water budgets were
sufficient to provide first order surface forcings for early climate models. However, starting in the early eighties, the need for more comprehensive biophysical models of surface
processes was recognized for a more realistic description of biosphere-atmosphere interactions. The first biophysically-based ESEMs were developed in the mid-eighties and, since
then, such type of surface process schemes have been widely used in climate models. The
characteristics of state-of-the-art, biophysically-based ESEMs available in the literature
are discussed in the next sections.
3.2. State of the art ESEMs
To date over 30 surface process models have been developed. However, they are in
some ways mostly based on two pioneering schemes, the Biosphere-Atmosphere-Transfer
Scheme (BATS) of Dickinson et al. (1986, 1993) and the Simple Biosphere model (SiB) of
Sellers et al. (1986). Figure 4 illustrates the basic sub-components of most state-of-theart ESEMs: i) A soil model ; ii ) A vegetation model; iii) a snow model; and iv ) a surface
runoff model. These su b-components, which are coupled through exchanges of energy and
water at their interfaces, are described in the next sub-sections.
SENSIBLE
EXCHANGE
A.''Dcly"amlc:
f.s.I.'arM:.
(r.J
Lui drlo
, I /
-0/
. ,
RAOIA TlVE EXCHANGE
MOISTURE
EXCHANGE
----T.--~----~L--,rf~~~~~~~-+~~~~ .
Low.' .01
lel'/'lOeralur.
T ..
1.100'" 101
•• ,.., Cd,,)
tEs:S::':::;;--r - r t
FIIocll,,; dl'lolrlt.ulIOf1 tahO
Is fl,ll'tC, . . 01 ¥'eoe'all'On If~
.011
column (4.)
- , ' ---' ·-1
Figure 4 Schematic representation of a state-of-the-art ESEM (BATS).