Caple AUF900 Uživatelský manuál stáhnout pdf (Strana 282)

280

ENSI Erfahrungs- und Forschungsbericht 2011

tween LGM1 and LGM2 are found for the North

Atlantic region especially in winter (December–

January–February, DJF), which is due to the pre-

scribed ocean surface that differs the most in this

area. In LGM2 the winter sea ice extends as far

south as 40°N and the Nordic Seas are widely cov-

ered by ice leading to a strong regional decrease

of SATs compared to PI. In contrast, the less exten-

sive southward sea ice extent in LGM1 leads to a

much less pronounced cooling, so that the two

LGM simulations differ by up to 30 °C over the

ocean especially in the Nordic Seas. As a further

consequence the cooling in Europe downstream

of the strong anomaly is less pronounced in LGM1.

As for the temperature the large-scale annual

mean precipitation anomaly patterns of the LGM

simulations with respect to PI agree well. In the

North Atlantic region the anomaly patterns for

DJF and summer (June–July–August, JJA) share

the main characteristics, namely generally drier

conditions except for a band of increased precip-

itation between 30° to 40°N reaching from the

eastern coast of North America to the Mediterra-

nean in winter and for some tropical region and

parts of the Fennoscandian ice sheet in summer

(Fig. 3a–d). At most locations in the mid- and high-

latitudes the anomalies are larger in winter than

in summer and the differences between LGM1

and LGM2 are more pronounced in winter. Com-

pared to LGM2 the DJF precipitation in LGM1 is

increased in the northern North Atlantic, in the

Nordic Seas, and in parts of the Mediterranean,

while a decrease is found at the lee side of the Fen-

noscandian ice sheet.

The impact of the radiative forcing changes be-

tween the LGM and MW leads to similar differ-

ences as for the ocean surface. The global mean

SAT in MWLGM is 0.8 °C higher than in LGM2,

but slightly lower than in LGM1, and the annual

mean SAT pattern is close to the ones in the LGM

simulations. As the northeastern part of the Atlan-

tic and the Nordic Seas are only partially covered

by sea ice in winter, the strongest anomalies with

respect to LGM2 are located in this region. Gen-

erally, the anomaly pattern is similar to the one

for LGM1, but with reduced amplitude especial-

ly around Newfoundland. Apart from the North

Atlantic the changes correspond to the forcing,

i.e. the southern hemisphere is slightly cooler in

MWLGM due to a strong reduction of solar inso-

lation that overcompensates the increased GHGs

forcing. For JJA, the SATs are globally higher in

MWLGM in agreement with the higher insolation

and the increased GHG concentrations.

The global mean precipitation in MWLGM is of

similar strength as in LGM1 and the spatial distri-

butions of the anomalies with respect to PI resem-

bles the ones of the LGM simulations for the annu-

al mean as well as for DJF and JJA (Fig. 3e and f).

The winter precipitation difference pattern LGM2-

MWLGM is similar to the pattern LGM2-LGM1,

but with reduced amplitudes especially in the sur-

rounding of Newfoundland. In contrast, for sum-

mer precipitation the pattern of LGM2-MWLGM

differs from the one of LGM2-LGM1 showing a re-

Figure 3:

Winter (DJF) and summer

(JJA) precipitation

anomalies with respect

to PI for LGM2 (a and b),

LGM1 (c and d), MWLGM

(e and f), MWLIN (g and

h), and MWUS (i and j).

Only values that are

statistically significant

at the 5 % level based on

the two-sided Student's t

test are colored.

1 2 ... 277 278 279 280 281 282 283 284 285 286 287 ... 303 304

Caple AUF900 Uživatelský manuál Strana 282

Komentáře k této Příručce

Caple AUF900 Uživatelský manuál Strana 282

Komentáře k této Příručce

Související produkty a manuály pro ne Caple AUF900