Changes in Andes Mountains snow cover from MODIS data 2000–2014

Abstract

Abstract. The Andes Mountains span a length of 7,000 km and are important for sustaining regional water supplies. Snow 10 variability across this region has not been studied in detail due to sparse and unevenly distributed instrumental climate data. limited between 8°S and 36°S due high frequency of cloud (>30% of the time) south and north of this range. We ran MannKendall and Theil-Sens analyses to identify significant areas of change in SP and snow line (the line at lower elevation 15 which SP=20%). We evaluated whether these trends in the context of temperature and precipitation (University of Delaware dataset) and climate indices (ENSO, SAM, PDO). North of 29°S has limited snow cover, and few trends in snow persistence were detected. A large area (70,515 km2) with persistent snow cover between 29-36°S experienced a significant loss of snow cover (2-5 fewer days of snow year-1). Snow loss was more pronounced (62%) on the east side of the Andes. We also found a significant increase in the elevation of 10-30 m year-1 south of 29-30°S. Decreasing SP correlates with decreasing 20 precipitation, increasing temperature, and climate indices and it varies with latitude and elevation. ENSO indices better predicted SP conditions north of 31°S, and the SAM better predicted SP south of 31°S.

How Does Snow Persistence Relate to Annual Streamflow in Mountain Watersheds of the Western U.S. With Wet Maritime and Dry Continental Climates?

“…Global gridded P products are typically much coarser than those available in North America and Europe and coarser than the MODIS-derived SP. These products are Water Resources Research 10.1002/2017WR021899 modeled and interpolated from station, radar and satellite data and can have considerable uncertainties (Bosilovich et al, 2008;Fekete et al, 2004;Kidd et al, 2012;Levy et al, 2017;Schamm et al, 2014) with heightened uncertainty of over 100% in high latitude and topographically complex areas including the Rocky Mountains, Tibetan Plateau, and Andes (Saavedra et al, 2018;Tian & Peters-Lidard, 2010).…”

Regional influence of ocean-climate teleconnections on the timingand duration of MODIS derived snow cover in British Columbia, Canada

“…Similarly to the ONI, we define PDO events of 5 consecutive months with values greater than 0.5 • C as positive (warm) and below -0.5 • C as negative (cool) phases (Kiem et al, 2003). 30 In this study, we summarize the seasonal teleconnection values of the ONI and PDO (Fig. 2).…”

“…The r S is a well suited metric to determine correlations with the multiple explanatory variables, but cannot easily be applied to predict hydroclimatology. 30 Using 10 thousand iterations of our workflow, we adjust the values of SD ON , SD OFF , and SD DUR with randomly selected values from the actual difference between the MODIS and ASWS data for each measurement to assess the impact of the inherent measurement uncertainty on our results. The error bars presented throughout this study were determined from the interquartile range of the resulting distribution of the iterated statistic.…”

“…10). The southern interior has experienced substantial land cover change caused by forestry (e.g., 30 Hansen et al, 2013) and has experienced extensive forest health outbreaks (Boon, 2012) and wildfires (BCWS, 2018) over the MODIS time period. The Fraser Plateau, for example, experienced a total of 26,869 km 2 of forest fire between 1917-2017 (inclusive), and of that nearly 40 % (10,253 km 2 ) occurred in 2017 (BCWS, 2018).…”

“…We summarize our results using hydrozones in order to capture much of the variability in SD over BC (Coulson and 30 Obedkoff, 1998). There are, however, other logical ways to group the province (e.g., 1 degree latitude and longitude groups, ecoprovinces, ecozones, etc.).…”