Last updated: September 19, 2024
Article
Climate and Weather Monitoring at Fort Larned National Historic Site: Water Year 2023
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Overview
Together, climate and hydrology shape ecosystems and the services they provide, particularly in arid and semi-arid ecosystems and across the Southern Plains (Woodhouse and Overpeck 1998). Understanding changes in climate, groundwater, and surface water is key to assessing the condition of park natural resources—and often, cultural resources.
At Fort Larned National Historic Site (Figure 1), Southern Plains Inventory and Monitoring Network scientists study how ecosystems may be changing by taking measurements of key resources, or “vital signs,” year after year—much as a doctor keeps track of a patient’s vital signs. This long-term ecological monitoring provides early warning of potential problems, allowing managers to mitigate them before they become worse. At Fort Larned National Historic Site, we monitor climate, among other vital signs.
Reporting is by water year (WY), which begins in October of the previous calendar year and goes through September of the water year (e.g., WY2023 runs from October 2022 through September 2023). This article reports the results of climate monitoring at Fort Larned National Historic Site in WY2023.
Reference: Woodhouse, C. A., and J. T. Overpeck. 1998. 2000 years of drought variability in the central United States. Bulletin of the American Meteorological Society 79(12): 2693–2714. https://doi.org/10.1175/1520-0477(1998)079%3C2693:YODVIT%3E2.0.CO;2.
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Climate and Weather
There is often confusion over the terms “weather” and “climate.” In short, weather describes instantaneous meteorological conditions (e.g., it’s currently raining or snowing, it’s a hot or frigid day). Climate reflects patterns of weather at a given place over longer periods of time (seasons to years). Climate is the primary driver of ecological processes on earth. Climate and weather information provide context for understanding the status or condition of other park resources.
Methods
A National Oceanic and Atmospheric Administration Cooperative Observer Program (NOAA COOP) weather station (Larned 2 KS # 144531) located 5.8 miles (9.3 km) east of Fort Larned National Historic Site has been operational since 2009 (Figure 1). The station typically provides a reliable climate dataset. However, in WY2023 it was missing data on 31 days. As a substitute, climate analyses in this year’s report use 30-year averages (1991–2020) and gridded surface meteorological (GRIDMET) data from the location of the visitor center at the park. Subsequent reports may revert to the weather station as the data source depending on future data quality.
GRIDMET is a spatial climate dataset at a 4-kilometer resolution that is interpolated using weather station data, topography, and other observational and modeled land surface data. Temperature and precipitation estimated from GRIDMET may vary from actual weather at a particular location, depending on the availability of weather station data and the difference in elevation between the location of interest and that assigned to a grid cell. Data from both the weather station and GRIDMET are accessible through Climate Analyzer.
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Results for Water Year 2023
Precipitation
Annual precipitation at Fort Larned National Historic Site in WY2023 was 23.18″ (58.9 cm), 2.55″ (6.5 cm) less than the 1991–2020 annual average. Monthly precipitation totals from October through April were below the 1991–2020 averages (Figure 2). In all other months, precipitation was above or near average.
Air Temperature
The mean annual maximum temperature at Fort Larned National Historic Site in WY2023 was 69.3°F (20.7°C), only 0.4°F (0.2°C) above the 1991–2020 average. The mean annual minimum temperature in WY2023 was 41.5°F (5.3°C), 1.3°F (0.7°C) below the 1991–2020 average. Mean monthly maximum and minimum temperatures in WY2023 differed by as much as 4.8°F (2.7°C; see December as an example) relative to the 1991–2020 monthly averages (Figure 2). Monthly mean minimum temperatures were below the 1991–2020 averages for the majority of the year, while monthly mean maximum temperatures were more variable and showed no apparent trend.
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Drought
Reconnaissance drought index (Tsakiris and Vangelis 2005) provides a measure of drought severity and extent relative to the long-term climate. It is based on the ratio of average precipitation to average potential evapotranspiration (the amount of water loss that would occur from evaporation and plant transpiration if the water supply was unlimited) over short periods of time (seasons to years). The reconnaissance drought index for Fort Larned National Historic Site indicates that WY2023 was drier for the third consecutive year relative to the 1991–2023 average from the perspective of both precipitation and potential evapotranspiration (Figure 3).
Reference: Tsakiris G., and H. Vangelis. 2005. Establishing a drought index incorporating evapotranspiration. European Water 9: 3–11.
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Authors: Kara Raymond, Andy Ray
Please cite this report as
Raymond, K., and A. Ray. 2024. Climate and Weather Monitoring at Fort Larned National Historic Site: Water Year 2023. Southern Plains Network, National Park Service, Pecos, New Mexico.
Please cite this report as
Raymond, K., and A. Ray. 2024. Climate and Weather Monitoring at Fort Larned National Historic Site: Water Year 2023. Southern Plains Network, National Park Service, Pecos, New Mexico.