Editing 53rd Weather Reconnaissance Squadron (section)

==Hurricane Hunter mission==
[[Image:Wc 130.jpg|thumb|right|WC-130H Hercules in flight]]
[[File:Lockheed Martin WC-130J.jpg|thumb|right|WC-130J Hercules on the ramp at [[Dobbins Air Reserve Base|Dobbins ARB]], Georgia, with another landing behind it, during reployment for Hurricane Katrina.<ref name="as">{{cite web| url= http://www.aviationspectator.com/more-aviation-photos?page=89&p1ff8age=17| title= WC-130| publisher= aviation spectator.com| access-date= 5 September 2010| archive-url= https://web.archive.org/web/20110707193952/http://www.aviationspectator.com/more-aviation-photos?page=89&p1ff8age=17| archive-date= 7 July 2011}}</ref>]]
The 53rd Weather Reconnaissance Squadron, using the call signs ''Teal 70'' to ''Teal 79'',{{efn|The 53rd picked up the call sign "Teal" in 1993 from the 815th, which had used it when designated the 815th Weather Squadron and again after 1991 when it contained a Hurricane Hunter [[flight (military unit)|flight]] in addition to its tactical airlift flights. As an active force squadron the 53rd had previously used the call sign "Gull."}} flies missions into [[tropical cyclone|hurricanes]] and weather systems for research purposes and observation. Although [[Remote sensing|satellite data]] has revolutionized [[weather forecasting|weather forecast]]ers' ability to detect early signs of tropical cyclones before they form, there are still many important tasks for which this information is not suitable. Satellites cannot determine the interior [[barometric pressure]] of a hurricane, nor provide accurate wind speed information. These data are needed to accurately predict [[tropical cyclogenesis|hurricane development]] and movement. Because satellites cannot collect the data and ships are too slow and vulnerable, the only viable way to collect this information is with aircraft. Meteorological parameters measured, in order of priority, are:
* Geographical position of the flight level vortex center (vortex fix) and relative position of the surface center, if known;
* Center [[Atmospheric pressure#Mean sea-level pressure|sea-level pressure]] determined by [[dropsonde]] or extrapolation from within {{convert|1,500|ft|m|abbr=off|sp=us}} of the sea surface or from the computed 925 [[Pascal (unit)|hPa]], 850 hPa, or 700 hPa height;
* Minimum 700, 850 or 925 hPa [[geopotential height|height]], if available;
* Wind data (continuous observations along the flight track) for surface and flight level;
* Surface wind data from [[Microwave radiometer|Stepped-Frequency Microwave Radiometer]] (SFMR);
* High density three-dimensional [[Weather radar#Velocity|Doppler radial velocities]] of the tropical cyclone core circulation;
* Temperature at flight level;
* Rain rate from SFMR;
* [[Sea surface temperature#Tropical cyclones|Sea surface temperature]]; and
* [[Dew point|Dew-point temperature]] at flight level.<ref>''National Hurricane Operations Plan of 2015'', p. 5–3.</ref>

The 53rd WRS is equipped with ten pallet-instrumented{{efn|Pallet instrumentation for the WC-130J's mission consists of a Communication Navigation Identification Unit (CNIU), Satellite Communication System (SATCOM), Advanced Vertical Atmospheric Profiling System (AVAPS) to receive and analyze dropsonde data, Atmospheric Sounding Processing Environment (ASPEN), and the Aerial Reconnaissance Weather Officer's computer with Weatherbird software package, all of which are described in the External Links. Between May 2007 and February 2008 all ten WC-130J Weatherbirds were also equipped with wing-mounted Stepped-Frequency Microwave Radiometer ("Smurf") pods, described separately. In 2009 the SFMR systems were retrofitted with a new antenna that during heavy rains resulted in an over-calculation of light winds, caused by water intrusion in the radome through drain holes in the new antenna. The problem was identified during [[Hurricane Felicia (2009)|Hurricane Felicia]] and found to have affected 50% of missions flown during the season. It was corrected in September 2009 by sealing the drain holes.}} WC-130J aircraft to collect the required meteorological data.{{efn|>AF s/n 96-5300 through −5302, 97–5303 through −5306, 98–5307 and −5308, and 99-5309.}} The area of responsibility for the "Hurricane Hunters" is from midway through the Atlantic Ocean west to the [[Hawaiian Islands]], although they have also been tasked to fly into typhoons in the Pacific Ocean on occasion, as well as gather data in winter storms.{{efn|The squadron previously tasked for tropical storm reconnaissance in the Western Pacific, the 54th WRS, was inactivated in 1987.}}  The Hurricane Hunters are tasked to support 24-hour-a-day continuous operations with the ability to fly to up to 3 storms at a time with a response time of 16 hours. This necessitates a mission organization of ten full-time aircrews and ten part-time.<ref name="53wrsmp"/>

The WC-130J employs a standard five person crew element of a pilot, co-pilot, [[Combat Systems Officer]] (CSO), aerial reconnaissance weather officer (ARWO), and a weather loadmaster/dropsonde operator, with a second loadmaster assigned when required. The ARWO is the flight meteorologist and acts as flight director inside the storm system. Operational crews train twice monthly at Keesler AFB and fly weather recon missions when available.<ref name="53wrsmp"/> 53rd WRS pilots and loadmasters go through their initial C-130J training at the [[314th Airlift Wing]]'s tactical airlift training center at [[Little Rock Air Force Base]], Arkansas. CSOs and ARWOs from the 53rd WRS have no formal school and train in-house at Keesler utilizing an [[Air Education and Training Command]]-approved syllabus for their specialized mission training.<ref>Losurdo, Major Marnee A.C. (20 January 2015). [https://www.403wg.afrc.af.mil/News/Article-Display/Article/681046/hurricane-hunters-investigate-training-options-at-kirtland-afb/ "Hurricane Hunters investigate training options at Kirtland AFB"], 403rd Wing Public Affairs. Retrieved 31 August 2015.</ref>

The 53rd WRS uses [[Henry E. Rohlsen Airport]] on [[Saint Croix, U.S. Virgin Islands|St. Croix]] as its primary forward-deployed location for North Atlantic basin operations. Each May since 1996, when it switched operations from [[Antigua]] to the [[United States Virgin Islands|U.S. Virgin Islands]] to operate from U.S. soil, the squadron prepositions maintenance equipment and materiel at Rohlsen in preparation for the coming season. From July through September three crews are commonly forward-deployed to St. Croix at any given time with rotations of a week's deployment per month.<ref name="vidn">{{cite news|author =Joy Blackburn|title=Hurricane Hunters Are Back|date=17 May 2013|work=The Virgin Islands Daily News, No. 22702}} p. 1</ref>

Since 1969, the 53rd WRS also performs winter storm weather reconnaissance off both coasts of the United States between 1 November and 15 April in support of the [[National Centers for Environmental Prediction]]. These missions are flown at the WC-130's [[service ceiling]] of {{convert|30000|ft|abbr=on}}, which subjects them to turbulence, lightning and icing. The crews collect data ahead of weather systems, dropping [[weather buoy]]s along their routes, before they move off the eastern seaboard to help determine if the conditions are right to intensify into [[Nor'easter]] blizzards. In 1997 and 1998, the Hurricane Hunters also flew winter storms in the [[Gulf of Alaska]]. The predetermined tracks are six to eleven hours in duration, with one to three missions flown per major winter storm event.<ref name="gs53wrs">{{cite web| url= http://www.globalsecurity.org/military/agency/usaf/53wrs.htm|title = 53rd Weather Reconnaissance Squadron| publisher = Global Security.org| access-date=2 September 2010}}</ref> Coverage of winter storms in the eastern Pacific has become standard during the month of February, operating [[Temporary duty assignment|TDY]] from either [[Elmendorf Air Force Base|Elmendorf AFB]], Alaska, or [[Hickam Air Force Base|Hickam AFB]], Hawaii.<ref name="hss">{{cite web | url= http://hurricanescience.org/science/observation/aircraftrecon/hurricanehunters/|title = Hurricane Hunters| publisher = Hurricanes: Science and Society| access-date= 11 December 2012}}</ref>

[[File:C130 MSGT 2 5-11-2018 medium.jpg|thumb|53rd Weather Reconnaissance Squadron and [[Federal Emergency Management Agency|FEMA]] staff discuss Hurricane Hunter aircraft operations aboard an Air Force Reserve WC-130J Super Hercules]]
The 53rd WRS works closely with the [[National Hurricane Center]] (NHC), a division of the [[National Weather Service]] (NWS) located in [[Miami]], that tracks hurricanes to provide early warning service for [[Atlantic basin]] storms. It maintains a subunit, the ''Chief, Aerial Reconnaissance Coordination, All Hurricanes'' (CARCAH), at the NHC as a point-of-contact and provides the staff and equipment to coordinate Department of Commerce requirements for hurricane data, assign weather reconnaissance missions and monitor all data transmitted from weather reconnaissance aircraft of DOC and the 53rd WRS.<ref name="53fs"/> To that end CARCAH is responsible for producing, publishing, and coordinating the Tropical Cyclone Plan of the Day (TCPOD) during hurricane season.<ref>''National Hurricane Operations Plan of 2015'', p. 5–5.</ref>{{efn|The TCPOD is available at <u>http://www.nhc.noaa.gov/</u> by clicking on ''Aircraft Recon'' under "Tools & Data" for ''Plan of the day''.}}

The 53rd WRS maintains similarly configured [[satellite communications]] [[ground station]]s within CARCAH at the NHC and its facility at Keesler to receive and process data from the aircraft. The Keesler ground station is maintained as a backup to the primary system at NHC, which has greater [[data stream]]ing capability, and would be manned by CARCAH personnel in the event of a long-term satellite communications failure at NHC. During temporary outages, 53rd personnel at Keesler act as operators and relay data from the aircraft by land line to the CARCAH ground station. Processed data is transmitted to the Weather Product Management and Distribution System (WPMDS) of the [[Air Force Weather Agency]] at [[Offutt Air Force Base|Offutt AFB]], [[Nebraska]], which then relays it to the NWS Telecommunication Gateway at [[Silver Spring, Maryland]], for worldwide distribution. The Keesler site has direct communications capability with WPMDS in the event of land line/internet failure between Keesler and the NHC. The system also provides backup transmission paths to WPMDS using local NHC servers and satellite connection to Keesler in the event of internet outages, except if an outage originates at Offutt.<ref>''National Hurricane Operations Plan of 2015'', p. 5–24.</ref>

===Tropical cyclone operational profiles===
When a tropical disturbance becomes suspect for development as a tropical or subtropical cyclone, the NHC assigns the system a [[Invest (meteorology)|temporary tracking ("Investigation") number]]{{efn|Numbers 90 through 99 in the cyclone numbering system are reserved for such disturbances. Although not required, the "90" series of cyclone numbers is assigned sequentially and normally reused throughout the calendar year. The number is further modified by a two-letter ocean basin code. Investigation AL97 (or "97L" in verbal shorthand) would be the seventh sequential disturbance in the North Atlantic basin, while Invest. EP92 (92E) is the second in the East Pacific basin north of the equator.}} and requests the 53rd WRS to determine if the winds are blowing in a counterclockwise rotation, indicating a "closed [[Cyclone#Structure|cyclonic circulation]]". This investigative mission is flown at an altitude of {{convert|500|–|1500|ft|abbr=on}} above the ocean surface in a pattern designated by the ARWO aboard the mission WC-130 based on observed conditions.{{efn|"Suggested" investigative patterns are the X, Box, and Delta patterns, described and illustrated at ''NHOP 2015'', pages 5–19 and 5–20.}} The ARWO, using a [[microwave radiometer|stepped-frequency microwave radiometer]] (SFMR, or "smurf"),<ref name="hss"/><ref name="smrf">{{cite web| url= https://www.403wg.afrc.af.mil/About/Fact-Sheets/Display/Article/192532/hurricane-hunter-weather-equipment/|title = Stepped-Frequency Microwave Radiometer fact Sheet| publisher = 403rd Wing AFRC| access-date= 12 December 2012}}</ref>{{efn|The SFMR is designed to continuously measure surface winds directly below the WC-130J, and is installed on the aircraft within a wing-mounted antenna pod. As the plane flies through a storm, the SFMR senses microwave radiation naturally emitted from foam created on the sea by winds at the surface. Computers determine wind speeds based on the levels of microwave radiation detected, extrapolated from the winds at the aircraft's altitude or from a dropsonde released from the aircraft. The SFMR can also determine rainfall rates within a system, which in addition to wind speeds at flight level, provides structural detail of the storm.}} continuously monitors ocean waves to determine wind speed and direction. The low-level wind and pressure fields provide an accurate picture for NHC forecasters. Investigative missions are usually flown during daylight and may be timed to arrive in the investigative area at first light in the morning or last light in the evening. Weak pressure gradients, large areas of calm, and light winds in areas of heavy convective activity often make vortex fixes difficult to obtain in areas of weak circulation, challenging the skills of the crews.

Once NHC determines that there is circulation within the disturbance, the mission becomes a sequentially numbered "fix" mission, conducted initially every six hours by rotating flights in cooperation with NOAA missions, and then at three-hour intervals as the storm moves within specified parameters.<ref name="53wrsmp">{{cite web | url= http://www.hurricanehunters.com/mission.html|title = The Mission of the Hurricane Hunters| publisher = Hurricane Hunters Association.com| access-date=30 August 2010| archive-url= https://web.archive.org/web/20100826005613/http://www.hurricanehunters.com/mission.html| archive-date= 26 August 2010 | url-status= live}}</ref>{{efn|A typical weather reconnaissance Tropical Cyclone Plan of the Day (TCPOD) is reproduced [http://www.nhc.noaa.gov/text/MIAREPRPD.shtml here]. Up to four 6-hour fixes per day are conducted when a system is within 500 nautical miles of landfall and west of 55°W in the Atlantic, and up to eight 3-hour fixes per day if within 300 nautical miles of the coast of the United States, Hawaii, Puerto Rico, the Virgin islands, or DOD installations. Up to two "synoptic surveillance" missions per day may be flown on the periphery of systems with a potential for landfall. (''NHOP 2015'', p. 5–12).}} During the "fix" mission, the ARWO directs the aircraft to the true center or ''vortex'' of the storm by monitoring the radar presentation, temperature, pressure, and mapping the wind fields as the aircraft makes left-hand turns. Vortices determined by individual parameters including visual observation may not coincide at the same geographic location. Surface and upper-level centers may be displaced by many miles. In order to make a reliable evaluation of its size and configuration, the crew flies through the disturbance using "Flight Pattern Alpha" consisting of [[cardinal directions|intercardinal]] headings with legs {{convert|105|nmi|km|sigfig=2}} in length.{{efn|"'''5.8.1. Flight Pattern ALPHA Operational Details. 5.8.1.1. Flight Levels and Sequence.''' Flight levels will normally be 1,500&nbsp;ft, 925 [[Pascal (unit)|hPa]], 850 hPa, or 700 hPa, depending on data requirements and flight safety. Legs will normally be 105 nm long and flown on intercardinal tracks (45 degrees off cardinal tracks). The pattern can be started at any intercardinal point and then repeated throughout the mission. Prior to starting an inbound or outbound track the aircrew should evaluate all available data, e.g., radar presentation, satellite photo, for flight safety. Once started on course, every effort should be made to maintain a straight track and the tasked altitude. A horizontal observation is required at each leg end point. This data is transmitted immediately. The ALPHA pattern may be modified to satisfy unique customer requirements (such as extending legs to examine the wind profile of a strong storm) or because of proximity of land or warning areas." (''NHOP 2015'', p. 5–19).}} The Alpha pattern is repeated at least twice during the mission, which will typically see a penetration of the eye of the system four times. Patterns may also be adjusted to meet circumstances encountered in the system. In August 2011, as [[Hurricane Irene]] neared the [[Delmarva Peninsula]] between landfalls, a 53rd WRS ARWO directed a pattern with shorter legs and more rapid turnarounds because of the proximity of land, making seven center fixes in one flight.<ref name="nlm"/> Flight weather data is continuously collected and sent directly to the NHC by satellite communications. Since the WC-130J is not equipped for aerial refueling, the alpha pattern continues until minimum fuel reserve is reached, or until the NHC has received all the data it requires.<ref name="53wrsmp"/>

Major hurricanes (Category 3 or higher in the [[Saffir–Simpson scale]]) are entered at approximately {{convert|10000|ft|abbr=on}} altitude.{{efn|Atmospheric pressure is determined by deviations from "standard levels" used by meteorologists worldwide. Stronger storms have lower pressures, and the lower the actual altitude from the standard level, the lower the pressure. The Hurricane Hunters use autopilot to fly a steady atmospheric pressure of 925 (2500&nbsp;ft/762&nbsp;m), 850 (4780&nbsp;ft/1457&nbsp;m), or 700 [[millibar]]s (9880&nbsp;ft/3011&nbsp;m) of pressure. Storms of category 3 strength or greater are flown at 700mb. By using a radar altimeter to measure actual altitude above the surface, the ARWO calculates the "height of standard surface" reported to NHC to make these determinations.}} While penetrating the [[Eye (cyclone)|eyewall]], a dropsonde is released to determine the [[maximum sustained wind]]s at the surface and a second dropsonde is released in the [[Eye (cyclone)|eye]] to detect the lowest pressure at the surface. After exiting the eye, the ARWO creates a Vortex Data Message that includes the precise latitude and longitude of the storm center as well as its maximum winds, maximum temperature, and minimum sea level pressure.{{efn|A description of the contents of the vortex data message is [http://jrscience.wcp.muohio.edu/downloads/VortexDataMessage.pdf here]. Standard sea level pressure is 1013 millibars. A "supplemental vortex data message" gives a cross-section of weather data at 15-nautical mile intervals, both inbound and outbound, along the 105-mile intercardinal legs to locate damaging winds in the storm's quadrants. Observation requirements are summarized in Table 5-1, page 5.5, ''National Hurricane Operations Plan 2015'', linked below. During active tropical cyclones, the most current vortex data message can be found at <u>http://www.nhc.noaa.gov/</u> by clicking on ''Aircraft Recon'' under "Tools & Data".}} The average duration of a "Hurricane Hunter" mission is ten hours, with five to six hours on station, depending on the distance of the storm from base, when tasked to perform three fixes at three-hour intervals.<ref name="nlm">{{cite journal|last=Mitchell |first=Capt. N. L. |year=2013 |title=Into the Storm: A Hurricane Hunter Member Describes Her Missions in the Air While Her Concerns are For Those on the Ground |url=http://www.mydigitalrendition.com/publication/?i=139668&p=35 |journal=The Officer |volume=LXXXIX |issue=January–February |archive-url=https://archive.today/20130216121616/http://www.mydigitalrendition.com/publication/?i=139668&p=35 |archive-date=16 February 2013 |access-date=8 January 2013 }}</ref>