Climate Assessment for the Sierra Nevada Network Parks

Edwards, Laura; Redmond, Kelly

Redmond. 2011. Climate Assessment for the Sierra Nevada Network Parks. This report provides assessment of existing weather and climate data for Sierra Nevada national parks (Yosemite National Park, Sequoia and Kings Canyon National Parks, and Devils Postpile National Monument) and makes some recommendations for how to best focus limited resources for effective monitoring of weather and climate in these parks. The National Park Service (NPS) Inventory & Monitoring (I&M) Program was established in 2000 as part of the Natural Resource Challenge, a long-term strategy to improve park management by increasing access to and reliance on high-quality scientific information. The Sierra Nevada Network (SIEN) is one of 32 I&M networks that will develop and provide scientifically credible information on the status and long-term trends in selected vital signs, or indicators of ecosystem condition. The SIEN comprises four units: Devils Postpile National Monument (DEPO), Sequoia & Kings Canyon National Park (jointly administered units referred to as SEKI, or individually as SEQU & KICA), and Yosemite National Park (YOSE). In 2007, the Western Regional Climate Center (WRCC) completed an inventory of existing weather and climate stations for each of the I&M networks. This document expands upon that knowledge base by discussing in-depth climate analyses, trends, and projections, and providing recommendations on how the SIEN can best allocate its resources to enhance current climate monitoring efforts. The SIEN requested that the WRCC perform an assessment of past and current climate data and information in the parks and of potential needs to inform development of a climate monitoring protocol. In so doing, we have considered existing literature, ongoing projects and programs, tools for accessing and manipulating data and information, and existing climate summaries. We have also performed a necessarily limited amount of new analyses to further develop and augment presently available information, specifically oriented toward the needs of the SIEN park units, and to fill gaps in our understanding of climate processes at work in this region. Here we summarize our findings and recommendations for the SIEN. Data analyses revealed a number of findings that are relevant to park management. Correlation analysis shows moderate east and west slope linkages, and also good north-south connections. Further, there are differences from month to month in how station temperature and precipitation relate across space, and these differences are elevation dependent. There is good correspondence between east-slope and west-slope temperatures in most months, but not enough that one set of stations can freely substitute for the other. The correlation analysis of Remote Automated Weather Stations (RAWS) showed that these stations have performed well and, for the most part, are generating good quality data. Another analysis based on assimilated upper air data showed that SIEN temperatures have been slowly warming in the past 30-35 years, that freezing levels have been rising in altitude (in seasons other than winter), and there are suggestions that high elevation trends may be slightly greater than those at lower elevations. The length and quality of climate records in the SIEN vary, though there are climate records of a century or more in or near all SIEN park units. In general, it is very difficult to find daily stations that have well-documented, consistent, and complete data records for periods of 6-10 decades, or more, from well-maintained sites. Our strongest recommendation is that at least a few such stations be given high priority for quality observations. Better high-altitude monitoring is needed. A few more high elevation stations are needed so that the 10000-14000 ft (3048-4267 m) band is adequately represented and bracketed. We recommend that each park unit identifies sever

Climate Assessment for the Sierra Nevada Network Parks

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