The tenth IMSC, Beijing, China, 2007 - International Meetings on ...

on instantaneous time scales, respectively. <strong>The</strong> statistical regression slope of turbulent energy
fluxes (sensible and latent heats) against available energy (net radiation, less the ground heat
flux) is 75.79% for the entire corn growing season, which indicates a lack of closure of 24.2%.
<strong>The</strong> imbalance is greatest during nocturnal periods. <strong>The</strong> regression slope of daytime data is
89% during the 10 days of mid-June, and gradually decreases to 67% during the 10 days of
early October, showing the seasonal decrease of energy closure with the corn growth. <strong>The</strong>
diurnal cycle of the energy utilizing ratios show that the energy closure in afternoons is better
than mornings. <strong>The</strong> instantaneous energy utilizing ratios are mainly concentrated within the
range of 0~1, but there also exist a number of values outside this range even during the
daytime. <strong>The</strong> latent heat is the main energy consumption form on all scales. <strong>The</strong> heat storage
term from the energy balance equation, may exceed the sensible heat in as long as seventy
days, which suggests it should not be omitted from the energy balance analysis of the corn
field. <strong>The</strong>re are phase differences that exist in the diurnal cycle of the energy components. <strong>The</strong>
phase of the heat storage term is often shifted to earlier times with respect to the net radiation.
We explore the lagging effect of turbulent fluxes as a new reason for failing to obtain the
energy closure. Results show that the energy closure ratios are improved on all time scales
when turbulent fluxes are lagged by 30 minutes to the available energy. As well as not only the
ratio points outside the range of 0~1, but also the earlier phase of the heat storage term are
improved in some degree.
Effects of land cover change on East Asian summer monsoon variability
Speaker: Eungul Lee
Eungul Lee
CIRES and U of Colorado-Boulder
eungul.lee@colorado.edu
Thomas N. Chase
CIRES and U of Colorado-Boulder
Balaji Rajagopalan
CIRES and U of Colorado-Boulder
<strong>The</strong> East Asian Summer Monsoon (EASM) is a tropical/subtropical monsoon covering
eastern <strong>China</strong>, the Korean peninsula, Japan, and the adjacent marginal seas. <strong>The</strong> region of
the EASM in this study will be 20°~50°N and 110°~145°E. We have shown in previous
research (Lee et al., in press) that there exist two components to the EASM, a northern
component and southern component, which are differentiated because they have different
causal relationships with heat sources in the surrounding oceans. Each component of the
EASM can be skillfully predicted by these causal relationships.
We wish to build on the previous research of Lee et al. and our proposed research will
address the following questions: (1) How do land factors affect the strength, seasonality, and
sub-seasonal variability of the EASM; (2) How do land and ocean factors interact to determine
these properties for the EASM; (3) whether statistical models using a combination of land
cover and ocean heating factors skillfully predict EASM precipitation; (4) whether models of the
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