Ocean-Atmosphere Observations Supporting Short-Term Climate Predictions (1994) / Chapter Skim
Currently Skimming:
'THE PRINCIPAL OBSERVABLES'
'THE PRINCIPAL OBSERVABLES'
Pages 29-47
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From page 30... ...
Essentially, the same response has appeared in report form (TOGA Numerical Experimentation Group, 1992)
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From page 31... ...
"We pointed out that in the atmosphere, we have little information about boundary layer structure, especially in the divergent trade cumulus regions, which tend to lie in oceanic regions without upper air observa tions. Since the ability of models to simulate and assimilate near surface data depends on boundary layer processes, we view this as a serious gap.
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From page 32... ...
( 1990) noted that on seasonal time scales critical differences in tropical Pacific wind stress products, on the order of 0.2 to 0.4 dynes/cm 2 , were found in wind regimes of surface convergence and significant gradients such as the Inter-Tropical Convergence Zone and the South Pacific Convergence Zone.
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From page 33... ...
180° ~ 40°N 40°N :WON 2Q•N EQ EO 20"S 20•s c ~ ~ i! c 400S 4o•s ~ ::z: ~ r., g 100°E 120"E 140°E 1110•E 180" 1110°W 1400W 120"W 1000W aoow ~ :ll:i • Atlas moorings o with current measurements ~ ~ c FIGURE 2 TOGA Tropical Atmosphere Ocean (TAO)
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From page 34... ...
It is worth emphasizing that the TAO winds provide not only a more suitable spatial and temporal sampling scheme for the equatorial zone than shipboard winds but also a uniquely homogeneous data set from the point of view of technique and quality control. Ship winds can be affected by shipto-ship differences in instrumentation, sensor installation and maintenance, perturbations to the airflow by the hull, and the effects of ship motion in a seaway on the measured wind.
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From page 35... ...
As the volume of buoy observations grew, particularly with expansion of the World Ocean Circulation ExperimentrrOGA Surface Velocity Program, it became possible to verify both VOS data and the ''calibrated" AVHRR data. In this vein the World Meteorological Organization (WMO, 1991)
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From page 36... ...
The Rosenstiel School of Marine and Atmospheric Sciences of the University of Miami has produced SST fields for the tropical Pacific with joint use of AVHRR and drifter data; these can be shown to satisfy the± 0.3°C accuracy requirement. The NMC SST field is now produced by using the buoy data to remove large-scale biases and trends in the AVHRR fields and to screen the VOS observations.
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From page 37... ...
lol lol lol lol lol 0 "' 0 N ~ "' 0 (l)
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From page 38... ...
. UPPER-OCEAN THERMAL STRUCTURE Together with surface wind stress and SST, the field of upper-ocean thermal structure is central to the successful initialization of coupled atmosphere-ocean models.
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From page 39... ...
PX ~ 0 ~ ~ ~ ~ ~ ro., - - - - - High DeneltY IJnM -- -- -Low Density LineS ~ ~ W.it.fMWf.@fi%ifE TRANSPAC ~ ~ ~ FIGURE 4 Proposed global network of XBT lines (U.S. WOCE Office, 1992)
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From page 40... ...
THE PRINCIPAL OBSERVABLES 29 TABLE 3 Occupation During 1990 of the VOS Lines Shown in Figure 4. (The first entry, PX-11 2, means that line PX-1 in Figure 4 was occupied two times in the year.
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From page 42... ...
work on space and time scales of tropical Pacific thermal variability; and similar work by Phillips, Bailey, and Meyers (1990) for the Indian Ocean.
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From page 43... ...
whose areas of interest clearly overlap. SEA LEVEL In the context of seasonal to interannual prediction, sea-level observations are useful as an integral constraint on model initialization fields and as a model validation data set.
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From page 44... ...
. Longterm moored velocity measurements along the equator have been integrated into the TOGA TAO array, and the Pan-Pacific drifters program provides basin-wide estimates of the circulation in the surface boundary layer.
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From page 45... ...
Operational sites 0 Planned X Required ! :l satellite transmitters ~ :::!
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From page 46... ...
Civilian aircraft meteorological reports using automatic equipment have increased, which is to be encouraged, but manually transmitted enroute reports have been reduced at the same time. It is now often the situation that an aircraft that is configured to give automatic enroute reports finds itself in a remote region out of range of receiving stations and thus gives no report at all.
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From page 47... ...
Finally, priority should be given to improving the technology of making and communicating surface and upper-air observations to the major data centers. In addition to the previously mentioned problems of temporal and horizontal spatial coverage, the data reported from operational soundings do not adequately resolve vertical structures (especially in the boundary layer)
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