Transcript NOAA P-3 activities during NAME

Regional scale sounding network enhancement
Michael Douglas, NSSL
Objectives of the activity
•
Although there are many possible topics for research related to moisture flux variability over the NAME
domain this study will focus on three. Each of these topics require a network of special observations to provide
a reliable answer. These topics are, together with their rationale:
•
1) Improve estimation of moisture fluxes from the eastern Pacific Ocean into the NAME Tier 1 domain (Gulf of
California and surroundings). This is needed to determine the relative importance of local (Gulf of California
evaporation) versus remote (eastern Pacific) moisture sources in the precipitation over the NAME Tier 1
domain and to determine if variations in precipitation over the Tier 1 domain are linked to variations in
moisture flux into the region from the eastern Pacific.
•
2) Improve the description of tropical wave variability over central Mexico and south of the Gulf of California.
Increasing the spatial density of wind soundings will provide a more accurate depiction of the strength and
structure of westward propagating waves that are believed to be the primary forcing for the so-called "gulf
surges", which are associated with major variations in the northward moisture flux over Tier 1;
•
and
•
3) improve the description of variations of the quasi-permanent heat low observed over the southwestern desert
of the US and northwestern Mexico. Fluctuations in the intensity of the heat low contribute to variations in the
pressure gradient along the Gulf of California and thus the up-Gulf moisture transport.
• 1) Improve estimation of moisture fluxes from the
eastern Pacific Ocean into the NAME Tier 1 domain.
This is needed to determine the relative importance of local (Gulf of
California evaporation) versus remote (eastern Pacific) moisture
sources in producing observed variations in precipitation over the Tier
1 domain.
Moisture flux supplemental sites
(only one radiosonde site)
• 2) Improve description of tropical wave variability over
central Mexico and south of the Gulf of California.
Increasing the spatial density of wind soundings will provide a more
accurate depiction of westward propagating waves that are believed to
be the primary forcing for "gulf surges", which are associated with
major variations in the northward moisture flux over Tier 1.
Westward propagating wave associated
with composite surge at 600 mb (NCEP reanalyses)
(observations north of Mexico City, over high interior plateau
needed to help specify wave structure)
• 3) improve description of the quasi-permanent heat
low observed over the southwestern desert of the US
and northwestern Mexico.
Fluctuations in heat low intensity contribute to variations in the
pressure gradient along the Gulf of California and thus the up-Gulf
moisture transport.
Special heat low network
5 low desert sites, very cloud free
seemingly over-sampled, but strong horizontal gradients in mean justify it...
Mean 700 mb winds (m/s) for 18 day period...
justify dense low-desert network
Platform description:
• Pilot balloon observations will be made at ~22 new sites
– Optical theodolites (1-2 persons required for observation, average
duration 30-50 minutes; computer/internet required to process/send
info in real-time)
– 20 balloons (30gm) per standard gas cylinder (~6 cubic m)
– Can be made almost anywhere, if communications no concern
• Radiosonde observations will be made at several high priority sites:
– West coast site of Baja California
– Torreon region (not resolved yet how to do this)
– Possibly Puerto Peñasco (when ISS not present)
– Note: these radiosonde systems are thermo only; winds come from
optical theodolite tracking unless other system can be arranged
Measurements strategies...
• Most soundings will be routine, predetermined, at synoptic
times.
• Some sites will, during the EOP, be capable of more
frequent observations.
Data dissemination plan...
• After post-processing the data will be distributed to JOSS.
• About 6 months required to process data...
Field coordination requirements
• IOP coordination:
– How will we participate in coordination?
• One representative will help at Tucson ops center...
– Will we need to coordinate with ship/aircraft and other systems?
• Not really.
– How will the sounding network be coordinated to satisfy budget
study objectives and also sample special events?
• Will function routinely, except for IOP’s
– Trade-offs between sampling anomalous versus special events...?
• Costs relatively low, can do both routinely, labor may be main
limitation for IOP’s
Expected coordination with data assimilation /
modeling groups...
• Suspect they will seek both data and comparisons with
basic analyses...
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October
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total obs's
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8010
HEAT LOW COMPONENT
Needles, CA
Lordsburg, NM
Tempe, AZ
Mexicali
Benjamin Hill
Mohawk, AZ
MOISTURE FLUX COMPONENT
Peñasco (add'l to SONET)
Cataviã, BC
Bahia Tortugas, BC
Isla Guadalupe, BC
Cd. Constitucion, BCS
La Paz, BCS
S. Jose d. Cabo, BCS
Isla Socorro, COL
Isla Clarion, COL
Isla Maria Madre, NAY
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TROPICAL WAVE SPECIFICATION
Alpine, TX
N. Casas Grandes, CH
Jimenez, CH
Torreon, DUR
Matehuala, SLP 15
Ocampo, COA
Durango, DUR
Zapopan, JAL
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What sites do we eliminate?
Training workshop for observers
prior to field phase...
• March-April time frame… students and other participants to
be involved in the field program activities
• Several days of lectures to give background to participants,
then field training activities.
• Site in northwestern Mexico, possibly one near Xalapa?