We evaluated the changes in extreme precipitation indices during the Mei-yu season in the western North Pacific based on the CMIP6 multi-model datasets. Five indices (RX1day, RX5day, SDII, R99p, and CDD) are analyzed. 10 CMIP6 models with 4 SSP scenarios are considered in this study. The indices associated with extreme rainfall intensity (RX1day, RX5day, SDII, R99p) are generally enhanced. The enhancements are statistically significant over southern China, central China, Taiwan, the Korean Peninsula, and southern Japan. On the other hand, the duration of CDD is slightly prolonged.The changes in the 4 rainfall intensity indices are more consistent between 10 models, but those of CDD are relatively inconsistent. As the SSP level raises, the enhanced extreme rainfall intensity becomes more identifiable and statistically significant.In addition, enhanced rainfall intensity and prolonged CDD are found in the eastern Bay of Bengal.

CMIP6, Extreme Precipitation, Mei-Yu

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This work investigates the impacts of land cover changes on the changes of surface environments in Taiwan in July. By using high-resolution regional WRF model experiments, we compare the changes of monthly mean of temperature (T), relative humidity (RH), and winds due to land cover changes between 1980 and 2016 in Taiwan (Chen et al., 2019). Changes of diurnal changes of T, RH, and land sea breeze are also investigated with the CWB station data of Taipei, Taichung, and Taitung. While model simulations have biases over the northern Taiwan, they seems to capture the patterns of temperature changes over the western Taiwan. It is found that, the temperature increase due to built-up land can be up to 2 degree over the urban area, which covers the cooling effects due to large-scale atmospheric changes.
Keyword : WRF model, Urbanization, Global Warming

Urbanization, Land cover use change, climate change, land-sea breeze

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Wet-bulb globe temperature (WBGT) is the most widely used index of heat stress nowadays, used to estimate the effect of temperature, humidity, wind speed (wind chill), and solar radiation on humans. To begin with, this study estimates WBGT with four parameters mentioned above, based on the hourly historical data of Taiwan weather stations from the Central Weather Bureau (CWB). Then, the study attempts to visualize the change of WBGT in Taiwan among years, months, and hours. Finally, the study applies the calculated WBGT to two regulations, including Heat Flag Conditions use by the U.S. military and Work-rest Standards during High-temperature operation used by Taiwan government, to see the change of flag conditions and rest time per hour regulated in Taiwan.

Wet-bulb Globe Temperature (WBGT), Work-rest standards, Global Warming

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The warming of ocean surface water has caused severe bleaching of global coral reefs. The mutualism between coral and its symbionts is disrupted due to the temperature rise. The latest research in our laboratory found that under coral bleaching threshold (CBT, 30°C), increased Fe availability enhances the growth of Symbiodinium. Here, we designed a novel experiment to test whether increased Fe availability affects the extent of bleaching at CBT, 30°C.

Coral bleaching, Symbiodinium, CBT, Trace metal

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Symbiodinium, a symbiotic microalgae resides in corals, provides its hosts energy to survive through photosynthesis. Rising sea surface temperature has caused serious coral bleaching and death recently. This study is to carried out experiments to validate our laboratory’s latest research, which is about the effect of Fe availability (Fe') on the growth rate of Brevolium minutum at high seawater temperature (30°C).

Symbiodinium, high sea water temperature, coral, trace metal

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Iron is a limiting factor for phytoplankton growth in the ocean. Studies show that the transformation between Fe(III) & Fe(II) would affect Fe bioavailability . And UV-B is an important factor to affect that. Ferrozine (FZ) is used to chelate Fe(II) reduced from Fe(III) in the experiments. The results show that UV-B would crucially promote the reduction and that FZ can chelate Fe(II) reduced from Fe(III). Finally, I draw a conclusion that I validate significant Fe photoreduction by UV-B.

Photo reduction of iron, UV-B, ferrozine

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