Evaluation of Cloud Vertical Structure Simulated by Recent BCC_AGCM Versions through Comparison With CALIPSO-GOCCP Data

ABSTRACT The abilities of BCC-AGCM2.1 and BCC_AGCM2.2 to simulate the annual-mean cloud vertical structure （CVS） were evaluated through comparison with GCM-Oriented CALIPSO Cloud Product （CALIPSO-GOCCP） data. BCC-AGCM2.2 has a dynamical core and physical processes that are consistent with BCC-AGCM2.1, but has a higher horizontal resolution. Results showed that both BCC-AGCM versions underestimated the global-mean total cloud cover （TCC）, middle cloud cover （MCC） and low cloud cover （LCC）, and that BCC_AGCM2.2 underestimated the global-mean high cloud cover （HCC）. The global-mean cloud cover shows a systematic decrease from BCCA-GCM2.1 to BCC_AGCM2.2, especially for HCC. Geographically, HCC is significantly overestimated in the tropics, particularly by BCC_AGCM2,1, while LCC is generally overestimated over extra-tropical lands, but significantly underestimated over most of the oceans, especially for subtropical marine stratocumulus clouds. The leading EOF modes of CVS were extracted. The BCC_AGCMs perform well in reproducing EOF1, but with a larger variance explained. The two models also capture the basic features of EOF3, except an obvious deficiency in eigen- vector peaks. EOF2 has the largest simulation biases in both position and strength of eigenvector peaks. Furthermore, we investigated the effects of CVS on relative shortwave and longwave cloud radiative forcing （RSCRF and RLCRF）. Both BCC_AGCM versions successfully reproduce the sign of regression coefficients, except for RLCRF in PC1. However, the RSCRF relative contributions from PC1 and PC2 are overestimated, while the relative contribution from PC3 is underes timated in both BCC_AGCM versions. The RLCRF relative contribution is underestimated for PC2 and overestimated for PC3.

Development and validation of a stability-indicating HPLC method for the determination of retigabine and its related substances in drug substances

A stability-indicating high-performance liquid chromatography（HPLC） method has been developed and validated for the separation and determination of Retigabine and its related substances. The chromatographic separation was achieved on Agilent Eclipse Plus C18 column（4.6 mm×150 mm, 5 μm）. The mobile phase was constituted of triethylamine-phosphate buffer as A and acetonitrile as B. The analysates were then eluted under the gradient conditions as description in this paper. The forced degradation study validated that the newly developed method was specific and selective to the degraded products. The performance of the method was verified according to the present International Conference on Harmonisation（ICH） guidelines for specificity, linearity, accuracy, precision and robustness. The correlation coefficients for Retigabine and its six impurities were greater than 0.999, which was shown in the regression analysis. Limits of detection（LOD） of these impurities were in the range of 0.0092%–0.0103%, indicating the high sensitivity of the newly developed method. Accuracy of the method was determined on the basis of recoveries to be between 96.49% and 118.35% for all impurities. Relative standard derivation（RSD） receiving in the repeatability and intermediate precision experiment, was less than 1.0%. The method can be successfully applied to routine quantify and stability testing Retigabine and its related substances in bulk drugs.

MULTIPLE EQUILIBRIA IN BAROCLINIC ATMOSPHERE BY THERMAL FORCING RELATED TO SUBTROPICAL HIGH

By using Lorenz’s moist general circulation model, a nonlinear and dissipative system describing atmospheric motion has been obtained in approximation of Low Order.The multiple equilibria and the transformation between the flow patterns of winter and summer, the latitudinal oscillation of subtropical high by thermal forcing and nonlinear interaction of general circulation are studied in this paper.The results show that the transformation of flow patterns is a discontinuous leaping, and is a process of resetting new flow pattern by rapid exchange inflow field.In the corresponding dry model, we cannot find the latitudinal oscillation of the center of subtropical high.In the moist model, after the thermal effect of water vapor is drawn into the model, nonlinear interaction appears between flow and heating fields.This effect helps to bring about the latitudinal oscillation of subtropical high.