Analysis of stable components in the extended-range forecast for the coming 10-30 days in winter 2010 and 2011

In this paper we try to extract stable components in the extended-range forecast for the coming 10–30 days by using empirical orthogonal function （EOF） analysis, similarity coefficient, and some other methods based on the National Center for Environmental Prediction （NCEP）/National Center for Atmospheric Research （NCAR） reanalysis daily data. The comparisons of the coefficient of variance of climatological background field and truth data in winter between 2010 and 2011 are made. The method of extracting stable components and climatological background field can be helpful to increase forecasting skill. The forecasting skill improvement of air temperature is better than geopotential height at 500 hPa. Moreover, this method improves the predictability better in the Pacific Ocean. In China, the forecast in winter in Northeast China is more uncertain than in the other parts.

The inter-visit variability of retinal blood flow velocity measurements using retinal function imager (RFI)

Background:To determine the inter-visit variability of retinal blood flow velocities(BFVs)using a retinal function imager(RFI)in healthy young subjects.Methods:Twenty eyes of 20 healthy young subjects were enrolled.RFI imaging was performed to obtain the BFVs in retinal arterioles and venules in a field measuring 7.3×7.3 mm^(2)(setting:35 degrees)centered on the fovea,and repeated measurements were obtained on two separate days.The inter-visit variability of BFVs was assessed by the concordance correlation coefficient(CCC)and coefficient of variance(CV).Results:At the first visit,the mean BFV was 3.6±0.8 mm/s and 3.0±0.7 mm/s in arterioles and venules,respectively,which were not significantly different from those at the second visit(the BFV of arterioles was 3.5±0.8 mm/s,and the BFV of venules was 3.0±0.7 mm/s,P>0.05,respectively).The CCC was 0.72 in the BFVs of arterioles and 0.67 in venules,and the CV was 10.8%in the BFVs of arterioles and 11.0%in venules.Conclusion:The inter-visit variability using the retinal function imager(RFI)with a large field of view appeared to be good and comparable to previously reported intra-visit and inter-eye variability.