www.ecco-group.org/abstracts/woce_lee4.txt


A Global Comparison of Ekman Pumping From Satellite Scatterometers and
Ocean Data Assimilation Estimates

Paulo Polito^1, Tong Lee^2, and Ichiro Fukumori^2
1. Inst. Nac. de Pesquisas Espaciais, Sao Paulo, Brazil
2. Jet Propulsion Laboratory, California Institute of Technology

Ekman pumping, a form of wind-driven upwelling, plays important
roles in upper-ocean dynamics, thermodynamics, and biology as well as
in boundary-layer meteorology.  Inverse models, such as those of
ECCO (Estimation of the Circulation and Climate of the Ocean, 
http://www.ecco-group.org/), estimate wind forcing through
ocean data assimilation.  Scatterometer data provide a stringent test
of the skill of the assimilation in estimating wind.  Ekman pumping  
obtained from various scaterometers are compared with those 
derived from ECCO model which assimilate TOPEX-derived sea level
anomalies using the adjoint and Kalman filter/smoother methods. 
Differences in Ekman pumping between scatterometer and assimilation
estimates are quantified in terms of the mean, standard deviation, and
correlation.  Change in Ekman pumping due to the assimilation is
analyzed to identify the spectral (frequency-wavelength) space over
which the assimilation has significant impact.  The comparison also
highlights aspects where the ECCO model and assimilation schemes need
improvement.

1
2	A Global Comparison of Ekman Pumping From Satellite Scatterometers and
3	Ocean Data Assimilation Estimates
4
5	Paulo Polito^1, Tong Lee^2, and Ichiro Fukumori^2
6	1. Inst. Nac. de Pesquisas Espaciais, Sao Paulo, Brazil
7	2. Jet Propulsion Laboratory, California Institute of Technology
8
9	Ekman pumping, a form of wind-driven upwelling, plays important
10	roles in upper-ocean dynamics, thermodynamics, and biology as well as
11	in boundary-layer meteorology. Inverse models, such as those of
12	ECCO (Estimation of the Circulation and Climate of the Ocean,
13	http://www.ecco-group.org/), estimate wind forcing through
14	ocean data assimilation. Scatterometer data provide a stringent test
15	of the skill of the assimilation in estimating wind. Ekman pumping
16	obtained from various scaterometers are compared with those
17	derived from ECCO model which assimilate TOPEX-derived sea level
18	anomalies using the adjoint and Kalman filter/smoother methods.
19	Differences in Ekman pumping between scatterometer and assimilation
20	estimates are quantified in terms of the mean, standard deviation, and
21	correlation. Change in Ekman pumping due to the assimilation is
22	analyzed to identify the spectral (frequency-wavelength) space over
23	which the assimilation has significant impact. The comparison also
24	highlights aspects where the ECCO model and assimilation schemes need
25	improvement.
26