Transcript PPT 13MB - global change SysTem for Analysis, Research

The Monsoon Systems
of the Americas in the
context of climate change
Carolina Vera
CIMA/Dept. of Atmos. and Ocean Sci. (UBA-CONICET)
Co-Chair WCRP/CLIVAR/VAMOS Panel
Variability of the American Monsoon Systems
•A WCRP/CLIVAR program
focused on the climate of the
Americas.
• Now in its implementation
phase
• Panel Co-Chairs:
C. Vera (UBA, Argentina)
W. Higgins (NOAA/CPC, USA)
WHAT ARE NAME and MESA?
The North American Monsoon Experiment (NAME) and the Monsoon
Experiment South America (MESA) are two internationally coordinated efforts
that aim to improve the description, simulation and prediction of the American
monsoon systems, their variability, and roles in the global water cycle.
CLIVAR is an interdisciplinary research effort within the
World Climate Research Program (WCRP)
CLIVAR Mission
To observe, simulate and predict Earth’’s climate system, with focus on oceanatmosphere interactions, enabling better understanding of climate variability,
predictability and change, to the benefit of society and the environment in which
we live.
http://www.clivar.org
Monsoon mature phase
Climatological seasonal mean precipitation
(shaded), 200-hPa streamlines (black contours)
& vertically integrated moisture fluxes (arrows)
How well do models reproduce the annual cycle?
Black: Observed, Purple: ensemble mean Light blue: individual members
Annual Cycle of Precipitation
9-member ensemble run of the
CPTEC/COLA AGCM forced by
observed global SST anomalies for
1982–1991 (Marengo et al. 2003, Clim.
Dyn.)
How well do models reproduce interannual variability?
Black: Observed, Purple: ensemble mean Light blue: individual members
Interannual variability of Precipitation anomalies
9-member ensemble run of the
CPTEC/COLA AGCM forced by
observed global SST anomalies
for 1982–1991 (Marengo et al.
2003, Clim. Dyn.)
VAMOS Approach
•Climate models have deficiencies in reproducing regional
climate features (diurnal cycle, transient variability, etc.)
•VAMOS seeks improved understanding of the key physical
processes (diurnal cycle, convection, topography, etc.) that
must be parameterized for improved simulation with
dynamical models.
•VAMOS modeling activities include: data assimilation,
global and regional AGCM, CGCM, seasonal forecasts,
hydrological models, etc.
•VAMOS employs a multi-scale approach ranging from
diurnal to interannual timescales and longer.
Diurnal cycle
NAMS
SAMS
21Z ~ 18 LST
21Z ~ 14 LST
South American Low-Level Jet Experiment
PIBALS
Radiosondes
NOAA/P-3
Missions
Enhanced
precipitation
gauge network
North American Monsoon Experiment (NAME)
NAME HYPOTHESIS:
The NAMS provides a physical
basis for determining the degree
of predictability of warm season
precipitation over the region.
The NAME 2004 Field Campaign (on
going) is an unprecedented opportunity
to gather extensive atmospheric,
oceanic, and land-surface observations
in the core region of the North
American Monsoon over NW Mexico,
SW United States, and adjacent oceanic
areas.
Diurnal cycle
2002-2003 Jul-Aug Diurnal Cycle of
Hourly Precipitation Frequency (NERN)
Precipitation Frequency
0.40
0.35
0-500
0.30
500-1000
0.25
1000-1500
1500-2000
0.20
2000-2500
0.15
2500-3000
0.10
Network Mean
0.05
0.00
1
4
7
10
13
16
19
22
Time of Day (LST)
Time of Maximum
hourly precipitation
frequency from NERN
Gochis et al. 2003
Wet-day hourly rain
rates for various
elevation bands in the
SMO from the NAME
Event Raingauge
Network (NERN)
Mesoscale Variability
05Z ~ 02 LST
Subtropical South America has the largest
fractional contribution of PFs with MCSs to rainfall
of anywhere on earth between 36 N and 36 S
(Courtesy Nesbitt & Zipser)
MCS mature stage time occurrence
frequency during SALLJEX. Bars in
green represent the period November
15 to December 31, in black January 1
to February 15 (Zipser et al. 2004)
Intraseasonal Variability
Typical
circulation
features of
the NAMS
accompany
wet and dry
surges
keyed to
Yuma, AZ.
H
+ T.
anom
H
L
- T.
anom
Typical
circulation
features of the
SAMS
accompany wet
and dry
conditions over
Southeastern
South America
(e.g. Diaz and
Aceituno 2003)
(Higgins et
al. 2004)
L
- T.
H
L
+ T.
anom
anom
Intraseasonal Variability (MJO)
Composite evolution
of 200-hPa velocity
potential anomalies
associated with MJO
events and points of
origin of tropical
disturbances that
developed into
hurricanes or
typhoons.
Interannual Variability
Role of land surface
conditions
Role of SST anomalies
(Doyle & Barros 2002)
Correlation
coefficients
between CPTEC
model anomalies
and observed
anomalies of
rainfall (Marengo
et al. 2003)
Role of Largescale circulation
10
Aerosol plume
produced by
biomass burning
at the end of the
dry season and
transported to
the south
(Freitas et al.
2004)
(Silvestri & Vera 2003)
0
PSI(200 hPa)
-10
-20
-30
-40
ND
Precipitation
-50
-80
-70
-60
-50
-40
Trends
JFM precipitation
trends
(Liebmann et al. 2004)
Precipitation
River stream
flow
SW Atlantic
SSTs
Normalized annual departures of SALLJ-event annual counts
The Global Climate Observing System
(GCOS) was established in 1992 as a
joint initiative of WMO,UNEP,
IOC,UNESCO, and ICSU to provide the
data necessary for climate system
monitoring, climate change detection
and response monitoring, application
to the development of national
economies, and research.
X
Tabatinga
X
VAMOS Contribution to
GCOS Action Plan for
South America
Project Brief:
Enhancement of the
GUAN network in Central
South America
Trinidad
VAMOS Contribution to GCOS Action Plan for South America
Project Brief: Enhancement of Sustained Surface and Subsurface
observations in western Subtropical South Atlantic
Climatological mean DJF precipitation.
Red dots: locations of the Pirata Southwestern
Extension
Light blue dot: location of the proposed site for an atlas
buoy.
VAMOS DELIVERABLES
• More comprehensive understanding of American climate
variability and predictability;
• Strengthened multinational scientific collaboration
across the Americas;
•
Observing system design for monitoring and predicting
the monsoon system of the Americas;
• Measurably improved climate models that predict
monsoon in the Americas variability from seasons in
advance.
VAMOS future challenges
• To strength links between climate variability and
climate change
VAMOS  WCRP-CLIVAR/WGCM  IPCC
• Link between climate variability and applications
VAMOS  START/AIACC in the Americas
(Big potential! Several VAMOS scientists are also
AIACC Scientists already)
Thank you!
http://www.clivar.org