Publication Date

2010-01-01

Availability

Open access

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Meteorology and Physical Oceanography (Marine)

Date of Defense

2010-11-03

First Committee Member

Dr. Brian Soden - Committee Chair

Second Committee Member

Dr. Shuyi Chen - Committee Member

Third Committee Member

Dr. Christopher W. Landsea - Outside Committee Member

Fourth Committee Member

Dr. Frank Marks - Outside Committee Member

Abstract

The main historical archive of all tropical storms and hurricanes in the North Atlantic Ocean, Caribbean Sea, and Gulf of Mexico from 1851-present is known as HURDAT. This official database of historical Atlantic tropical cyclones (TCs) is maintained by the National Hurricane Center (NHC). The original database of 6-hourly tropical cyclone positions and intensities was assembled in the 1960s in support of the Apollo space program to help provide statistical TC track forecasting guidance (Landsea et al. 2008; Jarvinen et al. 1984; Neumann, personal communication). Today, HURDAT is widely utilized and relied upon by many groups including research scientists conducting climatic change studies (e.g. Landsea et al. 1999), operational hurricane forecasters, insurance companies, and emergency managers (Jarrell et al. 1992). The accuracy of the HURDAT database is important to many; however, the original database contains many systematic biases and random errors (Landsea et al. 2008). Therefore, a reanalysis of the HURDAT database is necessary. The Atlantic Hurricane Reanalysis Project (AHRP) is an ongoing effort to correct the errors in HURDAT, and to provide as accurate of a HURDAT database as is possible with utilization of all available data. For this thesis, HURDAT is reanalyzed for the period 1944-1953, the first decade of the ?aircraft reconnaissance era.? The track and intensity of each existing tropical cyclone in HURDAT is reassessed, and previously unrecognized tropical cyclones are noticed, analyzed, and recommended to the National Hurricane Center Best Track Change Committee (NHCBTCC) for inclusion into HURDAT (existing TCs may be removed from the database as well if analyses indicate evidence that no tropical storm existed). Changes to the number of tropical storms, hurricanes, major hurricanes, accumulated cyclone energy (ACE), and U.S. landfalling hurricanes are recommended for most of the years of the decade studied. An error analysis for the decade is also provided. It is noted that all changes to HURDAT mentioned in this thesis are preliminary and have not yet been approved by the NHCBTCC. In addition to the HURDAT reanalysis, the second part of this study is conducted to determine whether the apparent recent increase in Atlantic Basin Saffir-Simpson Hurricane Wind Scale (SSHWS) Category 5 hurricanes is real or whether the increase is an artifact of recent technological advances and better observational capabilities. Several previous studies have stated that there has been an increase in the number of intense hurricanes both in the Atlantic Ocean and globally (e.g. Webster et al. 2005) and attribute this increase to anthropogenic global warming (AGW) and/or global climate change. Other studies (e.g. Landsea 2007) claim that the apparent increased hurricane activity in the record is an artifact of better observational capabilities and improved technology for detecting these intense hurricanes. This study delves deeper into the question of whether the recently observed increase in the number of Category 5 hurricanes in the Atlantic basin (late 1940s vs. 1990s-2000s period) is an artifact of better observations/technology or rather possibly due to climate changes. Ten Category 5 hurricanes were recorded in the Atlantic Basin from 1992-2007 [Hurricane Andrew (1992) to Hurricane Felix (2007)]. A new (fairly objective) methodology was created to determine how many of these ten recent Category 5s would have been recorded as Category 5s if they had occurred during the late 1940s using only the observations that would have been available with late 1940s technology. A new best track intensity was drawn for the entire lifetime of these ten recent Category 5s (using late 1940s technology), and it is found that only two of these ten (Andrew and Mitch) would have been recorded as Category 5 hurricanes if they had occurred during the late 1940s period. The results suggest that intensity estimates for extreme tropical cyclones prior to the satellite era are unreliable.

Keywords

Katrina; Central Pressures; Wilma

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