1. 6月18日学术报告：'Uncertainties in Measurements of Mesopause Temperature Trend Using the Bootstrap Monte Carlo Method' 时  间：6月18日（星期一）上午10：00 地  点：15楼会议室 题  目：'Uncertainties in Measurements of Mesopause Temperature Trend Using the               Bootstrap Monte Carlo Method' 报告人：Prof. David A. Krueger 单  位：Department of Physics, Colorado State University, Fort Collins, CO 80523, USA Abstract: Two methods, based on different assumptions, have been investigated for computing the uncertainty in the trend of mesopause region temperature measurements taken over 20 years.   The fitting model includes a trend, annual and semiannual variations, a solar effect, and an episodic term that can be associated with the Mount Pinatubo volcanic eruption.  There is a nonlinear dependence on parameters describing the episodic term. In the first procedure the unknown uncertainties of each measurement are assumed to be constant with time and are determined by assuming that we have a good model. The second procedure uses the Monte Carlo bootstrap method where one re-samples the data with replacement to obtain 'new' data sets which are fit to the model yielding a distribution of parameters. The standard deviation of the distribution for a parameter is taken to be the uncertainty in the parameter. The basic assumption in this method is that the data is ‘Independent and Identically Distributed’.  Although we have not been able to justify the assumptions of either method for lidar data, the two methods give essentially the same results.  Results of the bootstrap method for synthetic data will be compared to the 'input values'.

Qinxiu Li Posted at 2012-06-12 16:33 CST Last modified at 2012-06-12 16:43 CST Link to this poster Top