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Gustavo Jorge Goni* and Molly Baringer *[email protected] National Oceanic and Atmospheric Administration Atlantic Oceanographic and Meteorological Laboratory, Miami, FL NOAA Climate System Review September, 2008. Goals and status of XBT network. “operational” sustained. - PowerPoint PPT Presentation
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Gustavo Jorge Goni* and Molly Baringer*[email protected]
National Oceanic and Atmospheric AdministrationAtlantic Oceanographic and Meteorological Laboratory,
Miami, FL
NOAA Climate System ReviewSeptember, 2008
Goals and status of XBT network
Approximately 60% complete
Ocean observing system
57%
Total in situ networks 60 % complete May 2008
100%
40%
82%
43%72%48%21%
92%
“operational”sustained
70+ SOOP ships ocean obs900+ SOOP and VOS ships met bulletins
SHIP OF OPPORTUNITY Program (SOOP)
SOOP XBT deployments
High density (HD) mode: 1 XBT deployment every 25 km 4 transects per year
Frequently repeated (FR) mode: 6 XBT deployments per day (1 every 80 km) 18 transects per year
Low density (LD) mode: 4 XBT deployments per day (1 every 120 km) 12 transects per year Being replaced by Argo observations
XBT transects
Report on XBT network, OceanObs99: Neville Smith, D. Harrison, R. Bailey, O. Alves, T. Delcroix, K. Hanawa, R. Keeley, G. Meyers, R. Molinari, and D. Roemmich
Originally designed to investigate ENSO, SI variability
Science uses (Mostly HD transects)Eddy resolving, Identification of surface, subsurface currents, compute their mass transportsMeridional heat transportStrength of gyresValidation of modelsWater mass formationHeat budget
Operational uses:Data assimilation into modelsvalidation of models
SOOP FR XBT OceanObs99 recommendations
Adapted from: Neville Smith, D. Harrison, R. Bailey, O. Alves, T. Delcroix, K. Hanawa,
R. Keeley, G. Meyers, R. Molinari, D. Roemmich
The individual CLIVAR panels also provide recommendations, in addition to other regional, national and international recommendations.
25 recommended transects
The individual CLIVAR panels also provide recommendations, in addition to other regional, national and international recommendations.
SOOP HD XBT OceanObs99 recommendations
Adapted from: Neville Smith, D. Harrison, R. Bailey, O. Alves, T. Delcroix, K. Hanawa, R. Keeley, G. Meyers, R. Molinari, D. Roemmich
24 recommended transects
XBT and Argo observations2000-2007 (spatial distribution)
2000 2001 2002
2003 2004 2005
2006 2007
0
25000
50000
75000
100000
125000
# o
bs
erv
ati
on
s
Argo 7934 12210 20237 32420 48035 72203 95520 105000
XBTs (*) 12968 20592 19999 23303 26371 24098 21944 28000
2000 (inc)
2001 2002 2003 2004 2005 2006 2007
XBT and Argo observations2000-2007 (temporal distribution)
(*) Includes additional 4k XBTs per year that are not transmitted into the GTS
2006 ~22,000 deployments
XBT deployments
2007 ~28,000 deployments
40% Atlantic50% Pacific10% Indian
~20 transects done but not recommended
~11 transects recommended but not done
AX07 – long period signals
Courtesy of R. Molinari
AX08 – zonal currents in the TA
NECC
NEUCSEUC
SECC
NEC nSECcSEC
sSEC
Goni and Baringer, 2002
The FR-XBT Network and Ocean Data Assimilation Modeling
HRX line PX37/10/44 now has >16 years of quarterly sampling.
Time-varying heat budget for the region north of HRX line PX37/10/44. (Figs from Douglass, Roemmich and Stammer, 2008, submitted to DSR).
Heat transport from HRX data
Storage
A-S flux
From ECCO
Meridional heat advection
1990 1995 2000 2005
-0.4
0
0.4
0.8
1.2
35
ºS M
eri
dio
na
l He
at F
lux
(PW
)
ORCA 30ºS
1990 1995 2000 2005
-0.4
0
0.4
0.8
1.2
35
ºS M
eri
dio
na
l He
at F
lux
(PW
)
ECCO 35ºS
ORCA 30ºS
1990 1995 2000 2005
-0.4
0
0.4
0.8
1.2
35
ºS M
eri
dio
na
l He
at F
lux
(PW
)
ECCO 35ºS
ORCA 30ºS
AX18 35ºS
10 years
AX07 (zonal NA) AX18 (zonal SA)
The Oleander ProjectContinuous and simultaneous observations
URINOAA/NMFS, NOAA/AOMLSUNY
• 2 transects per week; 51 weeks per year
• Water sampling
• CPR since 1975
• XBTs since 1981
• TSG since 1992
• ADCP since 1993
• pCO2 since 2006
AX32
ISSUESGulf of Mexico and Caribbean Sea
1999-2005
ISSUES: HWRF and HYCOM
ISSUESGulf of Mexico and Caribbean Sea
A new challenge:XBT Fall rate equation
Recently published manuscriptsReport of workshop in OctoberWeb page by Tim Boyer (NODC)
Climatological isotherm depth estimates for the period 2000–2007 show positive differences between the XBT and Argo datasets that are statistically significant to 67%.
Is there a need for a re-evaluation of the XBT network and/or the observing system for upper ocean thermal studies ?
Some recommended transects are not being implemented (HD PX50).
Some recommended transect that are being implemented were not recommended (AX32-Oleander, HD AX98, LD/HD AX02).
There may be need to carry new transects (high latitude in NA).
There may be need to remove some transects (PX08).
Evaluate if some transects need to be sampled deeper than 800m.
Challenges
Challenges
Identification of all operational users (NCEP, US Navy’s MODAS, weather and climate model initialization...).
Identification of all scientific uses (data analysis, …)
Real-time transmission issues (Not all the data are transmitted in real-time into the GTS)
Can Argo floats alone provide adequate monitoring of the observing system for upper ocean heat storage ? If not, how can XBT and other platforms help ?
After 10 years of Argo, can we now evaluate if profiling float observation can reproduce XBT LD signals? May be it is too early to do this.
Evaluate if some transects need to be sampled with XCTD instead of XBTs.
There may not acceptable/sufficient scientific justification for some of the FRX transects.
Are current ocean models adequate to carry an evaluation of the system ? (OSSES)
BUFR and metadata.
XBT fall rate (work shop, manuscripts, data base).
Cost issues: ~$80 per XBT (~$35 when NOAA buys them) and $15 per transmission using Inmarsat (~$1.20 using Iridium, transition is currently is test phase).
Challenges
Drifter and Argo deployments
www.aoml.noaa.gov/phod/argo/opr
www.aoml.noaa.gov/phod/dac
Web pages
http://www.hrx.ucsd.edu/
http://www.aoml.noaa.gov/phod/goos/ldenxbt/index.php
www.aoml.noaa.gov/phod/hdenxbt/high_density_home.html