Publication Date

8-2025

Advisor(s) - Committee Chair

Jerald Brotzge, Zachary Suriano, Jun Yan, Xingang Fan

Degree Program

Department of Earth, Environmental, and Atmospheric Sciences

Degree Type

Master of Science

Abstract

This study compares historical precipitation and air temperature records of the Kentucky Mesonet (KYMN) to those of geographically close (i.e., paired) Cooperative Observer Program (COOP) and Automated Surface Observing System (ASOS) stations for the period 2011–2020. Basic statistics were used to quantify network differences. The comparison revealed systematic differences in precipitation and temperature between networks. The COOP standard rain gauge and ASOS heated tipping bucket measurements overestimated precipitation relative to KYMN’s weighing bucket models from Vaisala (VRG) and OTT (Pluvio2) during lighter precipitation days (< 18 mm). Conversely, during heavier rainfall days (≥ 18 mm), KYMN’s weighing buckets recorded higher values than either COOP or ASOS. Mean differences on days KYMN recorded < or ≥ 18 mm were statistically significant across networks. As expected, as the distance between paired stations increased, variance tended to increase while correlation decreased. Overall, network differences were statistically significant for the daily precipitation between KYMN and COOP pairs but not for the KYMN and ASOS pairs. Monthly difference estimates reflected daily differences. In general, COOP and ASOS tend to record warmer temperatures than KYMN, with the largest mean differences occurring near the temperature extremes. For windspeeds < 2.5 m s-1, COOP is warmer than KYMN (or KYMN is cooler than COOP); the trend reverses when windspeeds are ≥ 2.5 m s-1. COOP and ASOS sites are slightly less than ~1 °C warmer than KYMN when solar radiation exceeds ~300 W m-2. ASOS was warmer than KYMN during light winds and high solar radiation with a mean maximum temperature (Tmax) difference of 1.12 °C and COOP was warmer than KYMN during strong winds and high solar radiation with a mean Tmax difference of 0.71 °C. This comparison offers valuable insight into gauge/sensor behavior and network data quality when measuring precipitation and air temperature, and potential biases when computing long-term climatologies.

Disciplines

Applied Mathematics | Earth Sciences | Environmental Sciences | Oceanography and Atmospheric Sciences and Meteorology | Physical Sciences and Mathematics | Statistics and Probability

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