The exchange of momentum, heat, moisture, and gas across the air-sea interface plays a crucial role in atmospheric and oceanic circulations on variety of spatial and temporal scales. That is why improved understanding and realistic simulations of air-sea flux are critical to advancing oceanic and atmospheric prediction capabilities. This study provides the first detailed analysis of oceanic and atmospheric responses to the current-stress, wave-stress, and wave-current-stress interaction at the Gulf Stream using a high-resolution three-way coupled regional modeling system. This modeling system allows for the exchange of data fields between the atmospheric model—Weather Research and Forecasting (WRF), the ocean model—Regional Ocean Modeling System (ROMS), and the wave model—Simulating Waves Nearshore (SWAN) through the Model Coupling Toolkit (MCT). We perform four one-month simulations for October 2012, a time period when the impact of wind and waves is relatively large. The four experiments differ in how wind shear and surface roughness length are calculated in the bulk flux parameterization: 1) The control experiment calculates the surface roughness length by using the surface wind only (no shear from currents). 2) The current experiment interactively takes into account surface currents in the wind shear. 3) The wave experiment explicitly includes the sea-state parameters in calculating the roughness length. 4) The current-wave experiment computes the surface roughness by taking into account the current-induced shear and sea state simultaneously. In general, our results highlight the substantial impact of coupling currents/waves with wind stress on the air-sea flux exchange and ocean upwelling over the Gulf Stream. Two-way coupling of waves and wind stress causes wind stress (30-day averaged) increase up to 12% in 95th percentile of the model domain, and increases greater than 5% are found in 50% of the model domain. For two-way coupling of surface currents and wind stress, both positive and negative changes in wind stress (greater than 5%) are found at the Gulf Stream, with only small changes elsewhere. The pattern of wind stress change in the wave-current-stress coupling experiment is similar to that in the current-stress coupling experiment, with over 15% increase of wind stress at the Gulf Stream. The current impact on wind stress cancels out the wave impact outside of the Gulf Stream in the wave-current-stress experiment. Coupling currents/waves with wind stress also change the wind stress curl, which impacts the response patterns of upwelling and downwelling in the upper ocean. Changes in wind stress and its curl due to coupling processes lead to changes in SST and ocean current in the Gulf Stream. Considerable SST change (in excess of 1 oC) and ocean current change (in excess of 0.2 m/s) are collocated near the SST front region in the shape of warm/cold core eddies in all coupling configurations. We perform a mixed layer heat budget analysis to investigate the physical processes happening in the ocean mixed layer and their contribution to the SST changes. Substantial latent heat flux changes exceeding 20 W/m2 and sensible heat flux changes exceeding 5 W/m2 are found over the Gulf Stream in all coupled configurations. Sensitivity test shows that SST-induced differences of air-sea temperature and humidity are major contributors to the LHF and SEN changes. The coupling processes also change the surface wind convergence, which further impacts precipitation. / A Dissertation submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester 2017. / October 17, 2017. / Includes bibliographical references. / Mark A. Bourassa, Professor Directing Dissertation; Xin Yuan, University Representative; William Dewar, Committee Member; Jeffery Chagnon, Committee Member; Christopher D. Holmes, Committee Member.

Thesis (M.A.)--Boston University / A conceptual model of meterological temperature at a point is discussed in terms of components of variability, including hourly temperature trend, annual trend, and hourly, daily, monthly and yearly departures from trend. The notion is advanced that a matching conceptual model can be achieved in terms of components of persistence, or autocovariance of temperature. Some relationships between components of the two models are adapted from earlier work [TRUNCATED]

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Meteorology, 1963. / Vita. / Includes bibliographical references. / by Conway Leovy. / Ph.D.

Massachusetts Institute of Technology. Dept. of Meteorology. Thesis. 1965. M.S. / M.S.

The African Easterly Jet (AEJ) is one of the phenomena driving regional as well as global atmospheric circulation. Specifically, within the Sahel region, the AEJ and African Eastern Waves (AEWs) are main features that are linked and associated with the West African Monsoon. Both features determine rainfall and tropical cyclone development in this region. For certain years, the AEJ has a double core structure during the month of August when the jet is the strongest. The goal of this study is to identify distinct cases of the AEJ structure and determine the possible effect on AEW development. For this study, zonal and meridional wind data at 600 hPa was obtained from NCEP reanalysis during the month of August from 1948 to 2016. Maps of zonal wind were made to show the structure of the AEJ. Hovmöller diagrams of the 2.5 to 6-day meridional wind and maps of meridional wind variance were made to show the strength and track of AEWs. Results identified distinct cases where the structure of the AEJ deviated from its long-term mean, including the western (eastern) core being located north relative to the eastern (western) core. The double core cases with the southward eastern core has significantly stronger AEW activity with longer average tracks. However, on inter-annual scales, there is not a strong link between the AEW activity and east Atlantic tropical cyclone activity. The difference between the cases provide valuable insight about the relationship between the AEJ, easterly waves and tropical cyclone formation at the West African coast. / A Thesis submitted to the Department of Earth, Ocean and Atmospheric Science in partial fulfillment of the requirements for the degree of Master of Science. / Spring Semester 2018. / April 5, 2018. / Includes bibliographical references. / Sharon E. Nicholson, Professor Directing Thesis; Jeffrey Chagnon, Committee Member; Robert Hart, Committee Member.

The 10–20-day mode of surface winds is examined in the Indian Ocean, with special reference to the Arabian Sea, the Bay of Bengal, and the equatorial Indian Ocean during a strong (1994), weak (2002), and normal (1995) Indian summer monsoon. The winds are from the Cross Calibrated Multi-Platform (CCMP) gridded wind product version 2.0. Results indicate the 10–20-day mode of latitudinally averaged surface winds have zonal propagation in the western Indian Ocean (west of 75°E) and the signal appears stationary in the eastern Indian Ocean (east of 75°E) during May through September. The meridional propagation of the 10–20-day mode of longitudinally averaged surface winds appears weak during summer monsoon periods. The 10–20-day mode of surface winds in the Arabian Sea and the Bay of Bengal is more energetic than in the equatorial Indian Ocean. The signal of the 10–20-day mode appears more robust during a strong monsoon than during a weak monsoon in the Arabian Sea; however, no significant difference is found in the Bay of Bengal and equatorial Indian Ocean between strong and weak monsoons. Ensemble empirical mode decomposition (EEMD) analysis is used on a time series from the Arabian Sea to create an index for the 10–20-day mode in surface winds. Using this index, 75 cases of 15-phase 10–20-day events are identified and used to create composites of surface winds. Through these composites, a positive surface wind anomaly is found to appear at 60°E, centered on 15°S, and propagate zonally eastward to 90°E before reflecting back to propagate westward and then disperse off the coast of Madagascar. It is proposed that this oscillating positive wind anomaly is a feature of the southernmost cell of the 10–20-day convective double-cell structure that has extended farther south into the southern Indian Ocean and that this mode connects the Arabian Sea and southern Indian Ocean through the Somali Jet and surface winds. / A Thesis submitted to the Department of Earth, Ocean and Atmospheric Science in partial fulfillment of the requirements for the degree of Master of Science. / Summer Semester 2018. / June 28, 2018. / Includes bibliographical references. / Mark A. Bourassa, Professor Directing Thesis; Vasu Misra, Committee Member; Zhaohau Wu, Committee Member.

Thesis (Sc.D.) Massachusetts Institute of Technology. Dept. of Meteorology, 1952. / Vita. / Includes bibliographies. / by Richard M. Schotland. / Sc.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Meteorology, 1943. / Includes bibliographical references (leaves 31-33). / by William Marine Rowe. / M.S.

<p> Extreme fire behavior in the San Francisco Bay Area (SFBA) has historically been associated with strong offshore wind events referred to locally as Diablo winds. A 17 year surface-based climatological analysis was performed to establish a definition of Diablo winds and to identify their frequency and spatial distribution. Synoptic composites of events were constructed using North American Regional Reanalysis, and high resolution Weather Research and Forecasting (WRF) model simulations were used to investigate the mesoscale dynamics of three significant Diablo wind events. Diablo winds were defined as dry northeasterly, downslope winds that occur in the SFBA with minimum sustained wind speeds of 6 m s^&ndash;1. Climatological analysis results illustrate that Diablo winds most frequently impact the Coast Ranges nearest the Sacramento Valley and occur, on average, 2.5 times annually. The highest monthly frequency occurs in October when live fuel moisture is at its driest, creating the most severe fire danger for the SFBA during that time. Numerical simulations of significant Diablo events revealed that Diablo winds have complex character with contributions from small-scale downslope winds, as well as large-scale mountain waves interacting with terrain.</p><p>

Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Meteorology, 1952. / MIT copy bound with: A preliminary investigation of the vapor pressure of super-cooled water / Archibald A. Corrigan, Jr. 1952. / Bibliography: leaves 31-32. / by Daniel H. Lufkin. / B.S.