Date of Award
2025
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Atmospheric and Earth Science
Committee Chair
John Christy
Committee Member
Leiqiu Hu
Committee Member
Roy Spencer
Committee Member
Rob Junod
Research Advisor
John Christy
Subject(s)
Climatology--Research--California--San Francisco, Atmospheric pressure--California--San Francisco, California--Climate
Abstract
This data-recovery project and subsequent data analyses address the construction of a continuous, long instrumental record of sea level pressure for San Francisco, California, USA and examines what the time series may reveal about atmospheric patterns through time. Atmospheric pressure is a physical component which is associated with both daily and seasonal weather phenomena and is one of the most robust of the meteorological variables. Observational data of surface pressure (SFP) and later sea level pressure (SLP) were accessed from digital archives, with a large part of these being manually keyed from original observations on paper. San Francisco, being near sea level and with a small amplitude of temperature variations, allowed the conversion of SFP to SLP to be made with little ambiguity. There were four locations in the area, all near sea level, which provided observations and which were merged into a single time series using morning (~0700) and evening (~1900) daily values. The construction procedure identified and corrected for outlier values among other issues. The dataset begins on 1 Mar 1852 and ends with 31 Dec 2021. It was found, as expected, that prolonged extreme precipitation episodes are well-correlated with SLP while seasonal Sierra Nevada snowfall and nominal heavy rainfall events were less correlated. The phase of the El Nino-Southern Oscillation is found to have no significant relationship with San Francisco’s SLP. Pacific Decadal Oscillation phase also had no significant relationship. Comparison with CMIP6 model output indicated significant differences in basic patterns such as the phase and amplitude of the annual cycle of SLP.
Recommended Citation
Heaven, Brendan, "170 Years of San Francisco Sea Level Pressure" (2025). Theses. 771.
https://louis.uah.edu/uah-theses/771