Greenup values for interior alaska 1976 - Present

Greenup, the frequent rapid transformation of Interior Alaska from Brown space to spring green as the leaves deciduous trees burst forth, is suddenly enough to allow assignment of a single date in a given area to this culmination of a key biological process. Greenup is important for more than just an aesthetic or biological perspective. For example, once Greenup has occurred, there is a rapid increase in evapotranspiration. Which in turn has important consequences in the areas mesoscale meteorology. Here, dates for green around Fairbanks for more than 20 springs are correlated against several different temperature derived indices calculated entirely from routinely available climatological data. We examined a variety of degree day statistics and temperature thresholds. The relationships between these parameters and Greenup dates in Interior Alaska should be useful in projecting future greenup dates. They may also be useful to post analyze Greenup dates in years for which there is meteorological data but no surviving record of Greenup dates.植被返青期（Greenup）指阿拉斯加内陆地区由枯黄原野快速转为春日青绿的高频动态转变过程，即落叶树木抽芽展叶之际。当前已可通过单一时点赋值，精准锚定某一区域内这一关键生物过程的最终完成节点。植被返青期的重要意义远超美学与生物学视角。例如，植被返青发生后，蒸散量（evapotranspiration）会快速升高，进而对区域中尺度气象学（mesoscale meteorology）产生重要影响。 本研究针对费尔班克斯周边地区20余个春季的植被返青日期，与完全基于常规气候观测数据计算得到的多种温度衍生指数开展相关性分析。我们考察了多种度日数（degree day）统计量与温度阈值指标。上述参数与阿拉斯加内陆植被返青期之间的关联关系，既可用于预测未来的植被返青日期，也可用于回溯分析那些仅存有气象观测记录但未留存植被返青期实测数据的年份的返青日期。