Understanding Climate Change on the California Coast: Accounting for Extreme Daily Events among Long-Term Trends

Abstract

Abstract:The majority of weather station records indicate that surface air temperatures have been warming in California between 1950 and 2005. Temperature data from the mid-1990s to the present were analyzed for stations on California Central Coast near Big Sur (Monterey County) to better understand potential for climate change in this biologically unique region. Results showed that daily temperatures in both the winter and summer seasons have cooled the Big Sur coast, particularly after 2003. A current hypothesis is that observed coastal California cooling derives from greenhouse gas-induced regional warming of the inland Central Valley and Sierra Nevada foothill areas, resulting in stronger sustained on-shore sea-breeze flow. Closer examination of daily temperature records at a station location near the Big Sur coast revealed that, even as average monthly maximum temperatures (Tmax) have decreased gradually, the number of extreme warm summer days (Tmax > 37 °C) has also increased by several fold in frequency. Overall patterns in the station records since the mid-1990s indicated that diurnal temperature ranges are widening on the Big Sur coast, with markedly cooler nighttime temperatures (frequently in the wet winter season) followed by slightly higher-than-average daytime temperatures, especially during the warm, dry summer season.

Differing ecosystem responses of vegetation cover to extreme drought on the Big Sur coast of California

“…2,8 The majority of annual precipitation falls in the winter (November to March), annually varying from 40 to 150 cm throughout the range, with most falling on the higher mountains in the northern extreme. 1 During the summer, low clouds are frequently observed along the coast. 9 Summer fog is common below about 600 m (2000 ft) elevation.…”

“…11,13 Plant growth on the Big Sur coast can be highly variable from year-to-year and is generally limited by declines of soil moisture in the summer and by cool temperatures in the winter. 1 The annual production pattern for coastal plants is rapid growth in the late fall (November) after the first rains have returned, slow winter growth (December to February), and rapid growth again in spring (March to May). 14…”

Assessment of the Immediate Impacts of the 2013–2014 Drought on Ecosystems of the California Central Coast

“…The region has a Mediterranean climate of warm, dry summers and cool, wet winters, with localized summer fog near the coast (Hiatt et al 2012). Annual rainfall is highly variable and ranges from 40 cm to 155 cm throughout the region, with highest event totals normally falling on the higher mountains in the northern extreme of the study area during winter storms (Potter 2014a). During the summer, fog and low clouds are frequent along the coast.…”

“…Plant growth on the Central Coast can be highly variable from year to year and is generally limited by declines of soil moisture in the summer and by cool temperatures in the winter (Potter 2014a(Potter , 2014b. The annual production pattern for coastal grasses is rapid growth in the late fall (November) after the first rains have returned, slow winter growth (December-February), and rapid growth again in spring (March-May) (Shreve 1927, Corbin et al 2005.…”

“…This can lead to the formation of steep elevation gradients in air temperature regimes, humidity, and other climatic factors. This region of the state is continuously subjected to extreme climatic events (Hiatt et al 2012, Potter 2014a, frequent wildfires, and human development impacts, together affecting wildlife populations, native plant communities, soil conservation, riparian zones, and water quality.…”