WRF Environment Assessment in Guangzhou City with an Extracted Land-use Map from the Remote Sensing Data in 2000 as an Example

Mesoscale urban environment forecast combined with WRF is a current frontier in international academic. Taking Guangzhou as an example,the new land-use model presented by the present authors,the existing USGS and MODIS models in WRF were firstly compared to the remote sensing model in this article.The comparison result shows that the land-use model presented by the authors has the highest similarity with the remote sensing data. Secondly,the new land-use model was used to replace the defaulted land-use data in WRF for simulation. By comparing this simulation results with the WRF results using the defaulted USGS and MODIS model,it was showed that the geographic models have a great impact on the mesoscale environment forecast result. Also,the geographic information model presented in this article shows the best accuracy when comparing with the observation data. Results in this study are going to be an important reference in the contemporary international forefront of mesoscale urban environment studies by WRF.

Distribution of living radiolarians in spring in the South China Sea and its responses to environmental factors

Using a planktonic net(62-?m mesh) and a Rose-Bengal staining method, we studied the spatial distribution of living radiolarians in spring along two sections of the South China Sea(SCS) in spring and discussed the responses of living radiolarian distribution to tropical environmental factors. Generally, the highest abundance of living radiolarians occurred at the depth range of 25–75 m, where the chlorophyll-a maximum and the highest primary productivity were. In contrast, the maximum living abundance occurred in the top 25 m in cold eddies in the open seas and the abundance decreased with depth. We found that the inhibition effect of changing salinity(due to runoffs) on living radiolarians was much stronger than the promotion effect of mesoscale cold eddies. We observed that large variation of temperature was unfavorable for living radiolarians. The dominant species composition consisted of tropical-subtropical warm species. We identified some indicator species for tropical environments. Living Didymocyrtis tetrathalamus tetrathalamus could be an indicator for tropical surface water or mixed-layer water, and even for tropical oligotrophic water. Living Tetrapyle octacantha could be used to indicate tropical thermocline and eutrophic environment. Living Acanthodesmia vinculata could indicate tropical surface and subsurface waters. T. octacantha and A. vinculata should only be used as indicators for upwelling in the open seas, i.e., far away from river mouths. Living Siphonosphaera polysiphonia preferred to form colonies, which might be related to the effect of warm eddies. Living Cyrtopera laguncula and living Cornutella profunda occurred in the tropical upper layer, even in the surface layer, which suggests that they should not be used as indicators for intermediate and deep waters.