Feasibility Analysis
The Hurricane Rainband and Intensity Experiment
(RAINEX)
Title:
P.I./Institution:
Location:
Period:
Facilities:
Hurricane Rainband and Intensity Experiment
R. Houze (U of Wash), S. Chen (U of Miami)
Miami and Tampa, Florida
15 August – 30 September 2005
ELDORA and Dropsondes on NRL P3
Summary:
The Hurricane Rainband and Intensity Experiment (RAINEX) is a joint
NCAR/NOAA project that will use ELDORA and GPS dropsondes to observe the
kinematic structure of hurricane rainbands in conjunction with one or two NOAA
P3s. The GPS Dropsonde will be used to document the environment of the
rainbands from the mid-troposphere into the hurricane boundary layer and
provide the thermodynamic framework for the dual-Doppler radar observations
and numerical model simulations. The dropsonde data in combination with the
extensive dual-Doppler coverage will provide the thermodynamic properties of
the air seen to be flowing through and under the rainbands.
Resources Involved:
(1) The PI requested ELDORA on the NRL P3 for 100 research hours, with flights
lasting 8-10 hours each. Due to the nature of hurricane climatology, RTF
assumes that the flights will be broken into 3 to 5 specific hurricane flight
episodes or IOPs.
(2) The RAINEX PIs requested one 4-channel AVAPS GPS dropsonde system
operating from the NRL P3 and 450 GPS dropsondes (300 for the NRL P3
and 150 for the NOAA/P3s). The dropsonde capability is not currently
available on the NRL P3. The addition of this system will require
modifications to the fuselage and the existing AXBT chute on the aircraft and
the design and fabrication of a new (possibly pressurized) dropsonde launch
system for the NRL P3. Flight testing prior to the standard upload of
equipment will be required at Pax River to verify proper operation and safety
of ejecting dropsonde from the P-3.
(3) In the NRL feasibility, the Navy requires two upgrades to the basic avionics
support infrastructure on the P3: a high altitude radar display in the cockpit
and a TCAS collision/warning system. Both of these systems will have to be
installed by the Navy or a Navy-contractor such as NAVAIR.
(4) For safe flight operations, a real-time data link between the NOAA and the
NRL P3s is requested to transmit and display the NOAA P3 belly radar images
as well as satellite data in the NRL cockpit with the ability to overlay current
P3 positions. This system does not currently exist on any aircraft and will
require significant development efforts by both NOAA and ATD.
NRL P3 Flight Hours:
The following is NRL’s flight hour estimate to conduct the RAINEX project
independently of any other ELDORA project:
Flight Hrs
Ferry (Install/De-install)
10
Ferry (Tampa & return)
6
Ferry (fwd deployed airfield & return) TBD (15 hrs*)
Test (equipment checkout at JEFCO)
5
Mission
100
Total
121 (136)
* One fwd deploying ferry to Barbados or St. Croix will take roughly 15 hours.
Location:
In order to facilitate operational coordination and based on the NRL limitation of
only conducting research flights concurrently with a NOAA P3, the NRL aircraft
and crew will be co-located with the NOAA crew during the entire flight phase of
the project. This P3 base will be MacDill AFB in Tampa, Florida where the NOAA
P3s are at home. Additional airfields may be required if the P3s are re-directed to
other locations dependent on the hurricane paths and developments. Airfields
suitable for the NOAA WP3D will be considered suitable for the NRL P3.
The ELDORA technical and engineering staff will also be located in Tampa, FL to
be close to the NRL P3. Local work space near the aircraft will be needed for
ground support of the instrumentation package while computer ground stations
could be located at a hotel or the University of South Florida, primarily to avoid
firewall issues and security clearances at MacDill.
The scientific staff will be based at the Operations Center at the Rosenstiel School
of Marine and Atmospheric Sciences in Miami, Florida (RSMAS) right across
from HRD. Scientific staff will drive/fly from Miami to Tampa on a regular basis
to interact with the technical and operational staff as necessary and to meet the
P3s before each mission. If missions occur on consecutive days, scientific staff
will stay in Tampa for the duration of the IOP (defined as the end of flying on a
specific hurricane).
If the forecast indicates a quiet period for the next 7-10 days after the end of an
IOP, it is proposed that ATD staff be allowed to return to Boulder for the break.
Additional airline tickets were included in the budget for on-call staff to travel to
Tampa for emergency or unexpected problems with ELDORA. A crew change at
the mid-point of the experiment is proposed and can be coordinated with the
NRL crew exchange.
Scheduling Requested:
The proposed project dates for flight operations is 15 AUG-30 SEP 2004. NRL P3
587 is the only NRL aircraft suitable for installation of the ELDORA radar.
Assuming a guaranteed 5 weeks for installation and 5 days for de-installation, the
following are the effective dates to be scheduled:
Payload Install
Project flights
De-install
==> 11 JUL – 12 AUG
==> 15 AUG – 30 SEP
==> 3 OCT – 7 OCT
ATD and NRL will be able to support RAINEX aboard the NRL P3 aircraft on the
dates and location requested. However, RTF received numerous requests
including two additional ELDORA and several dropsonde requests that compete
for staffing and equipment. The “RTF comprehensive feasibility”, which was
provided to NSF, specifically addresses overall RTF limitations with respect to
field project support and will need to be taken into consideration before a final
decision is being made.
Instrumentation Upload:
A four-week period will be required to install ELDORA and the GPS dropsonde
system, to complete the standard RAF upload of the in-situ instrumentation and
aircraft data system, to re-install the data/display system, communications
equipment and to produce the pre-project calibrations. A fifth week must be set
aside for local flight testing and checkout of all ATD systems. Typically this takes
2-3 flights of roughly 1-2 hours each. In addition, 2-3 test flights with the NOAA
P3s near Tampa are needed to ensure that satellite communications and radar
data transfer from one aircraft to the other are functioning properly. Four to five
days are needed for de-install at the end of the project.
Instrumentation:
(1) Standard Equipment:
VHF Radios: The PI requested both voice and data communications between
the NRL-P3 and the NOAA P3s. Two VHF radios will be available on the NRL
P3. The radio in the cockpit is permanently installed and limited to the exclusive
use of the pilots; a second radio for scientist-to-scientist communications will be
installed by RAF at the scientist table. The PIs will be asked to decide on one of
two possible radio configurations – either a headset with an integrated
microphone or a hand-held microphone with separate table top speakers. The
VHF radio link broadcasts between 117.0 – 135.975 MHz with 25 KHz spacing.
Satellite Phones: Air-to-ground and aircraft-to-aircraft communications for
the scientific staff include real time telemetry of data and “text chat” via SATCOM
internet access. Two Iridium satellite phones will be installed by RAF on the NRL
P3 – one of those is for exclusive use for transmission of RAF data and the chat
set-p, the second one is strictly used for voice.
(2) New Equipment
NRL Requirements: In the Navy feasibility NRL requested/recommended the
installation of the following equipment, which has not been previously
flown/installed on the NRL P3:

High altitude (RADAR) altimeter w/ flight station repeater in the cockpit

TCAS recommended for safety of flight during multiple aircraft operations

2 sets of lap belts to be installed in the flight station for the observers during
turbulence

Data link capability between the NOAA and the NRL P3s to transmit belly
radar pictures with the ability to overlay the current NRL P3 position.
Radar Altimeter: The high altitude radar altimeter was flown during BAMEX
on the NRL P3, however no altitude indicator was installed in the cockpit. To
accommodate NRL’s request, a separate indicator would have to be purchased
(approx. $10K-15K) and installed. This installation will require modification of
the aircraft cockpit to accommodate the display and installation of wires
connecting this “slaved” unit to the radar controls located in the ADS rack. RAF
personnel cannot/won’t conduct any modifications within the cockpit area. Such
work must be assigned to Navy personnel qualified to do the job or contracted
out to a suitable avionics contractor. Since the radar altimeter belongs to NCAR,
it will be removed after the project. If NRL chooses to leave the cockpit indicator
permanently installed, it will be inoperable once NCAR removes the altimeter.
TCAS: The TCAS system is a complex piece of avionics that will require
modifications to the aircraft’s cockpit configuration and must be linked to various
components of the aircraft’s standard avionics package. Such a system should be
installed permanently on the aircraft and will require the services of a certified
avionics contractor. The necessary equipment will have to be purchased. A
similar system was recently purchased and installed on the NSF/NCAR C-130 for
about $190K. The Navy will have to provide approval for a permanent change to
the platform. It is currently not known whether NOAA installed TCAS systems
on their P3s.
Seat belts: With regard to additional seat belts, the installation of new safety
equipment must remain the responsibility of the Navy. ATD cannot accept any
responsibility for this type of basic infrastructure.
Data link:
For safe flight operations in the vicinity of hurricanes, the NRL crew as well as
the PIs request frequent satellite and P3 belly radar updates on the NRL P3. This
is probably the most critical and time consuming development for RAINEX and
requires a significant contribution and involvement from NOAA and ATD/RDP.
No system currently exists on the NOAA P3 that generates geo-located,
compressed radar scan data and sends them to the ground. If such data can be
delivered, they will be combined with satellite images and real-time aircraft
tracks on the ground to generate composite images to be sent to the NRL P-3
similar to what was done in BAMEX. RAINEX will require an additional display
capability in the cockpit to be useful for flight operations, which will require
networking wiring in the cockpit. In BAMEX, frequent satellite transmission
dropouts were experienced especially when the aircraft turned; these types of
drop outs should be expected in RAINEX as well. Concerns of bandwidth
limitations and slow rate of data transmission will have to be investigated further
and actual data transmission time probably will not be known until the system
has been developed. Overall the development of such a data link and display
system will require additional funding for 2 to 3 months of an RDP software
engineer (45-50K). Additional costs are involved on the NOAA side, where a
NOAA software engineer will have to do the necessary development work on the
sending side.
GPS Dropsonde System
Currently the NRL P3 does not have the capability to deploy dropsondes.
Discussions were held in the past between ATD and NRL regarding the
fabrication of a sleeve insert into the already existing AXBT chute on the aircraft.
Since the dropsondes will be deployed at altitude, NRL has indicated that a
pressurized launch system will be required. The design and fabrication of a new
chute will be carried out by DFS in consultation with RTF and NRL. The free fall
chute which currently exists in the P-3 will be used for the installation location of
the launch tube. The free fall chute however is vertical (no slant) to the fuselage,
this is not the optimum angle for reliable ejection of dropsondes from any
aircraft. Due to the vertical ejection of the sondes from the aircraft, the Navy will
require detailed analyses of the sondes ejecting from the aircraft and the design
of a launch tube that will extend beyond the fuselage skin ($50K). The ejection of
dropsondes from the P-3 will require flight tests early in the year ($35K). Special
funds will be needed to perform this work. Complete stress analysis of the floor
loading will be required for the dropsonde equipment rack. Normally the RAF
aeronautical engineer would conduct a stress analysis to evaluate floor loading
however, due to HIAPER commitments, this task will have to be completed by an
alternate consultant such as NAVAIR ($20K).
Installation of the chute requires approximately 4 flight tests (1.5 hours each) to
verify proper launching of the dropsondes from the aircraft and to ensure that all
NRL safety requirements are met. These test flights should be carried out at Pax
River well before the start of the installation at JeffCo.
The dropsonde system requires the installation of a new 400 MHz UHF antenna
in the bomb bay area of the aircraft. The antenna installation will have to be
carried out by an outside contractor such as Platform Systems. The installation
of a new antenna and new equipment will require a EMC test prior to obtaining
flight clearance ($20K). Additional wiring within the aircraft, which will take
about 2 to 3 days, will be done at JeffCo.
Operations:
(1) NRL P3
The PIs adjusted their original flight profiles for RAINEX to reflect the NRL
restrictions and limitations stated in a previous RAINBANDS feasibility study.
The NRL P3 will fly a track parallel to and outside the hurricane rainband which
may or may not be flown in conjunction with a NOAA P3 flying parallel on the
other side of the rainband. Though the proposal stipulates that NRL will not
cross the rainband, it is noted that the rainband can be as turbulent and
convective as the eye wall.
In order to facilitate flight safety, NRL recommends approval of funding to send
two NRL pilots to NOAA AOC during present year hurricane season to gain flight
experience in the hurricane environment. NOAA extended an invitation to NRL
to join on the next hurricane flight in mid-September 2004. NRL also requested
a meeting with the scientists responsible for planning the specific flight profiles
along with a NOAA AOC representative. Such a meeting is planned for 15-17
November in Miami, FL.
(2) ELDORA:
ELDORA will be deployed to observe the kinematic structure of hurricane
rainbands in conjunction with one or two NOAA P3s. ELDORA will be operated
at 10,000-12,000 ft outside the outer rainbands. The F/AST scanning technique
will be employed to obtain the necessary dual Doppler radar observations.
Radar Parameters:
Number of PRFs: 2
Number of frequencies: 2-4
Antenna rotation rate: 100-140 deg/sec
Gate spacing along beam (m): 75-150 m
Number of gates: 500
Minimum sensitivity needs: 10 dBZ at 50 km
The operation of the radar will be adjusted to maximize the spatial resolution to
obtain detailed storm structures. The desired sensitivity of 10 dBZ at 50 km is
quite possible as ELDORA routinely saw 5 dBZ echoes at 50 km during previous
experiments. Due to the lack of reflectors over the ocean, the clear air capability
of ELDORA will not be as good as those experiments over land. The PIs should
be aware that there is typically second trip echo and sidelobe contamination in
the ELDORA data. ELDORA will be able to accurately measure airflow within the
precipitating systems; however, attenuation will occur, especially in the region
behind intense convection. The automatic dual-PRF unfolding of radial velocity
will allow an unambiguous velocity interval of greater than 80 m/s.
(3) Dropsondes:
The initial flight plan for the NRL P3 is to fly about 10 missions during the sixweek period dropping approximately 20 dropsondes per mission. The planned
temporal spacing between dropsondes is about 20 minutes, corresponding to
about 120 km horizontal spacing between drops. Dropsondes will be released
over the Atlantic and Gulf of Mexico region.
Please note that RTF staff will need to coordinate with other hurricane research
aircraft in the selection of sonde transmitter frequencies in the 400 MHz
meteorological band to prevent RF interference during the field program.
Personnel:
(1) RTF - ELDORA
ELDORA operational staff usually includes one project manager/scientist, one
radar scientist, one engineer, two technicians, and one data manager. In
RAINEX, have a physical separation between the aircraft and the data analysis
center will require an additional scientist in the field. Salary for such a temporary
help was included in the cost estimate. The EDLORA scientific staff will require
extensive help from NOAA/AOML/HRD to assist in flight operations since ATD
staff has only minimal experience in flying in a hurricane environment. It would
be most beneficial to have a NOAA flight scientist on every NRL P3 flight. The
ELDORA lead scientist will serve as the primary point of contact regarding
scientific issues.
(2) RAF
The system upload and deployment interval for the project overlap with the
HIAPER Progressive Science missions and ongoing supplemental development of
key new capabilities on that aircraft. Therefore, RAF can only provide two
(instead of 4) technicians for support of this project. The RAF technicians will
install the data system, calibrate the in situ sensors and provide in-flight system
operation and hardware maintenance for the duration of the field project.
Additionally, one scientist and one software engineer will be deployed for the
initial 10 days of the project to setup the RAF computer support.
(3) RTF - GPS Dropsonde
One RTF staff will be required to operate the system during the field program and
provide preliminary data results to the PI. There is a possible scheduling conflict
of personnel resources during the installation and testing of AVAPS with
HIAPER installation for software engineering support.
(4)RDP - Networking and SA
A System Administrator is required at the beginning of the project to set up the
field network and the ELDORA real-time displays, and to solve other potential
problems associated with the ELDORA set-up. That person will also establish an
exposed host to support an ATD data network linking RAF and RTF systems and
to provide the necessary communication links to the field operations center and
the internet.
Crew Duty Limits:
The NRL P3 crew and ATD staff will use the same crew duty limits that NOAA
operates by.
Additional Requirement:
All scientists, ATD staff and visitors who need to fly on the NRL P3 will have to
take the NRL NP4 Project Specialist training, held once a month in PAX River,
Maryland. The training involves a pressure chamber test, a swim test and a
medical clearance. A one-time, one-flight waiver can be requested. RTF will
provide (loan) flight suits for PIs and visitors. Steel-toed boots have to be
provided by the PIs themselves although NCAR does have a couple of spare pairs.
Please contact ATD for details of the survival training. Since the NP4 Training is
only valid for 4 years, some ATD staff will have to be re-certified for RAINEX.
This feasibility analysis assumes that all required ATD staff will pass the survival
training before the project begins.
Data Processing Requirements and Policies:
(1) ELDORA Data
RTF will set up a single ELDORA engineering workstation at MacDill AFB. An
ELDORA data processing computer network consisting of one Sun workstations
and a Linux server will also be set up in Tampa. ATD is currently exploring
locations other than AOC to avoid firewall issues and security clearances at the
MacDill. This network will be used by RTF staff to be able to perform in-field
quality control of ELDORA data and for preliminary processing of those data. A
Linux workstation will be set up at the data analysis center in Miami to house the
ELDORA data.
A T-1 line or better will be required if the RTF workstations cannot be housed at
the University of Southern Florida or NOAA. Since the PIs and the aircraft are
located in different places, internet data transfer becomes the ONLY method to
deliver data in the field between Tampa and Miami.
RTF expects RAINEX to acquire ~120-150 Gbytes of raw, non-redundant data
from ELDORA and the Weather Avoidance Radar (WARDS). The following list
outlines the delivery schedule we anticipate to achieve.
Data Quality Checks:
Preliminary Dataset:
Case Priority List:
Aircraft Attitude/Position:
Ground Echo Processing
(ELDORA table compilation)
Processing to DORADE
In field, continuing post-field
In field, assessable via ftp
Developed during and after field phase
Field Phase + 2 months (this info is provided
by RAF and required to complete ELDORA
data processing
Field Phase + 3 months correction
Begin: Field phase + 2-3 months
Partial shipments, depending upon PI priority
list. Anticipate a rate of about 1-2 flights per
week for processing and review.
Data delivery will be delayed by 3 months each for every additional ELDORA
project approved for summer 2005.
After each flight, RTF will generate quick-look (raw) data in sweep file format on
disk. These data are usually available 24 hours after a flight or at the
end of an IOP. Please note that in case of the airplane not returning to Tampa
after a flight, no data can be provided to the Operations Center in Miami until the
P3 returns to MacDill AFB. However, a laptop computer will be kept on the NRL
P3 to examine data and identify any potential conflicts in case the P3 will be
stationed at a remote site. Data will be copied from the original disk to produce
quick look data for the ELDORA scientist to review. This “mobile” system does
not presently consists and requires some development work on both hardware
and software.
RTF does no longer provide raw data on tapes in the field. Authorized PIs can
assess these files via internet.
The DORADE data will be generated after the ground echo processing is
completed, usually 2-3 months after the field experiment. During the DORADE
generation, all currently known problems will be corrected with the best guess of
navigation correction factors from RTF and the most recent version of aircraft in
situ and positioning data. Any discrepancies identified after the generation of the
DORADE data will be fixed either in the Translator and/or in SOLO. This
situation may happen after the final dataset is generated. The RTF manager will
decide if regeneration of DORADE data is necessary. PIs should note that RTF
only applies one navigation correction files for each header in each day. The
drift, ground speed and tilt errors for each individual leg are often deviated from
the bulk numbers RTF applied to the dataset. It is expected that additional finetuning of the navigation corrections (if desired) will be performed by PIs with
programs supplied by RTF.
The final dataset will be stored on the NCAR Mass Storage and can be
downloaded via the internet. RTF will no longer deliver data on either Exabyte or
DLT tapes.
(2) RAF Data
The RAF will ship a ground station to Tampa to be used for downloading aircraft
data files and to produce quick look data sets at the aircraft deployment site. The
RAF will send an initial set up team of one scientist and one software engineer to
ensure that this capability is fully functional. Standard low rate (LRT) data
processing will be done for this project. The standard RAF data format is
netCDF. A network link will be required to send data files back to JeffCo for an in
depth QA review by the RAF project management staff.
Delivery times for the final data products will vary. Post-project activities
performed on the standard RAF instrumentation package include sensor
calibration, final data processing, and a detailed quality assurance review of the
final data products. RAF data sets are typically available within about three
months of the completion of the field deployment.
(3) Dropsonde Data
RTF personnel will provide data quality control checking of the dropsonde data
using ASPEN software. Quick look data can be made available to the PIs once the
aircraft returning to the base. Providing dropsonde data in real time is currently
not considered. At the current bandwidth of 2400 baud, transferring of dropsonde
data would require five minutes per dropsonde, during which no flight track data
could be provided. ATD did consider the installation of a third antenna and a third
Iridium phone on the NRL P3 however the cost for such an addition is substantial.
The final QC processed data will be provided via FTP files. The file format is in
ASCII or net CDF. The standard dropsonde data products will be provided to the
investigator three months after the completion of the project.
Conclusion:
(1) NRL P3
NRL has agreed to fly the proposed flight pattern during RAINEX assuming that
the requested safety upgrades have been made. However, these upgrades will
require additional funding from either NRL or NSF and the installation will have
to be carried out by the Navy.
(2) Dropsondes:
The dropsonde system is a new instrumentation requirement for the NRL P3. With
sufficient time, the installation of the dropsonde system is feasible. Special NSF
funds outside the deployment pool will be required for the installation of a
dropsonde system onto the P3 prior to this program for the design/ analysis/
installation and flight testing of the dropsonde launch tube, electronics rack and
UHF antenna for the NRL P3.
(3) Data Link:
The data link between the NRL P3 and the NOAA P3 is a major development
effort that requires support from NOAA. Without collaboration from NOAA, such
a system cannot be designed by ATD alone.
The table below shows a rough estimate of additional costs presently not covered
by the Deployment Pool. Special funds for an additional 430K needs to be
identified.
Instrument
Indicator radar altimeter
TCAS
NOAA Belly Radar Data Link
NRL P3 Data Link
Equipment Rack Stress Analysis
for AVAPS
Responsible Party
Navy
Navy
NOAA
ATD/RDP
Contractor
Estimated Cost
15K
190K
unknown
50K
20K
Launch tube stress analysis and
certification
Antenna mods for AVAPS
EMC
Flight Tests for dropsondes at Pax
Launch tube (pressurized)
PSI
50K
PSI
Navy
Navy
ATD/DFS
10K
20 K
35K
40K