Longwave emission trends over Africa and implications for Atlantic hurricanes

Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 44 (2017): 9075–9083, doi:10.1002/2017GL073869.The latitudinal gradient of outgoing longwave radiation (OLR) over Africa is a skillful and physically based predictor of seasonal Atlantic hurricane activity. The African OLR gradient is observed to have strengthened during the satellite era, as predicted by state-of-the-art global climate models (GCMs) in response to greenhouse gas forcing. Prior to the satellite era and the U.S. and European clean air acts, the African OLR gradient weakened due to aerosol forcing of the opposite sign. GCMs predict a continuation of the increasing OLR gradient in response to greenhouse gas forcing. Assuming a steady linear relationship between African easterly waves and tropical cyclogenesis, this result suggests a future increase in Atlantic tropical cyclone frequency by 10% (20%) at the end of the 21st century under the RCP 4.5 (8.5) forcing scenario.J.P.D., K.B.K., and L.Z. Acknowledge support from the Strategic Environmental Research and Development Program (SERDP) (RC-2336).2018-03-0

Longwave Emission Trends Over Africa And Implications For Atlantic Hurricanes

The latitudinal gradient of outgoing longwave radiation (OLR) over Africa is a skillful and physically based predictor of seasonal Atlantic hurricane activity. The African OLR gradient is observed to have strengthened during the satellite era, as predicted by state-of-the-art global climate models (GCMs) in response to greenhouse gas forcing. Prior to the satellite era and the U.S. and European clean air acts, the African OLR gradient weakened due to aerosol forcing of the opposite sign. GCMs predict a continuation of the increasing OLR gradient in response to greenhouse gas forcing. Assuming a steady linear relationship between African easterly waves and tropical cyclogenesis, this result suggests a future increase in Atlantic tropical cyclone frequency by 10% (20%) at the end of the 21st century under the RCP 4.5 (8.5) forcing scenario

Solid-Phase Synthesis of Highly Fluorescent Nitrogen-Doped Carbon Dots for Sensitive and Selective Probing Ferric Ions in Living Cells

Carbon quantum dots (C-Dots) have drawn extensive attention in recent years due to their stable physicochemical and photochemical properties. However, the development of nitrogen-doped carbon quantum dots (N-doped C-Dots) is still on its early stage. In this paper, a facile and high-output solid-phase synthesis approach was proposed for the fabrication of N-doped, highly fluorescent carbon quantum dots. The obtained N-doped C-Dots exhibited a strong blue emission with an absolute quantum yield (QY) of up to 31%, owing to fluorescence enhancement effect of introduced N atoms into carbon dots. The strong coordination of oxygen-rich groups on N-doped C-Dots to Fe³⁺ caused fluorescence quenching via nonradiative electron-transfer, leading to the quantitative detection of Fe³⁺. The probe exhibited a wide linear response concentration range (0.01–500 μM) to Fe³⁺ with a detection limit of 2.5 nM. Significantly, the N-doped C-Dots possess negligible cytotoxicity, excellent biocompatibility, and high photostability. All these features are favorable for label-free monitoring of Fe³⁺ in complex biological samples. It was then successfully applied for the fluorescence imaging of intracellular Fe³⁺. As an efficient chemosensor, the N-doped C-Dots hold great promise to broaden applications in biological systems

Identification, characterization, and synthesis of process-related impurities in antiproliferative agent TQ-B3203

<p>Liposoluble camptothecin derivative, research name TQ-B3203, is a recently developed investigational antiproliferative agent by our group. The structure of TQ-B3203 is 2-(hexadecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yl 7-ethyl-camptothecin-10-yl succinate, containing an SN-38 component, a trolox component, a succinic acid linker, and a hexadecanol chain. In this study, the process-related impurities of bulk TQ-B3203 were identified, characterized, and synthesized. Seven major impurities were revealed based on the mass spectrum (MS) and nuclear magnetic resonance (NMR) spectral data. They were characterized as SN-38 (IMP-I), trolox (IMP-II), 2-(dodecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yl 7-ethyl-camptothecin-10-yl succinate (IMP-III), hexadecyl 7-ethyl-camptothecin-10-yl succinate (IMP-IV), 2-(tetradecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yl 7-ethyl-camptothecin-10-yl succinate (IMP-V), 4-(2-(hexadecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yloxy)-4-oxobutanoic acid (IMP-VI), and 4-(2-(octodecyloxycarbonyl)-2,5,7,8-tetramethylchroman-6-yloxy)-4-oxobutanoic acid (IMP-VII). The probable origin of the impurities from the preparation process of TQ-B3203 was discussed.</p

Moisture source variations for summer rainfall in different intensity classes over Huaihe River Valley, China

Rainfall is one of the most influential climatic factors on regional development and environment, and changes in rainfall intensity are of specific concern. In the Huaihe River Valley (HRV), heavy rainfall is a primary trigger of floods. However, the difference in the origin of moisture contributed to heavy rainfall and light rainfall is rarely studied and not entirely understood. This study analyzes the rainfall moisture sources in association with different categories of rainfall intensity over the HRV during 1980–2018 using the Water Accounting Model with ERA-Interim reanalysis and precipitation observations from China Meteorological Administration. The results show that the moisture for the HRV summer rainfall is mainly from terrestrial subregion (40%), the Indian Ocean (27%), the Pacific Ocean (25%), and the local HRV (8%). In addition, moisture sources differ substantially between light and heavy rainfall. Specifically, the local HRV contributes more moisture to light rainfall (12%) compared to heavy rainfall (4%), whereas the Indian Ocean contributes more to heavy rainfall (33%) than to light rainfall (20%). The grids located in the southern source region make higher contribution ratio in heavy rainfall than in light rainfall. These results suggest that moisture from distant oceanic areas, especially the Indian Ocean, plays a crucial role in intense summer rainfall, whereas moisture from the land sources covering local grids plays a dominant role in light rainfall in the HRV.Water Resource

Longwave emission trends over Africa and implications for Atlantic hurricanes

Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 44 (2017): 9075–9083, doi:10.1002/2017GL073869.The latitudinal gradient of outgoing longwave radiation (OLR) over Africa is a skillful and physically based predictor of seasonal Atlantic hurricane activity. The African OLR gradient is observed to have strengthened during the satellite era, as predicted by state-of-the-art global climate models (GCMs) in response to greenhouse gas forcing. Prior to the satellite era and the U.S. and European clean air acts, the African OLR gradient weakened due to aerosol forcing of the opposite sign. GCMs predict a continuation of the increasing OLR gradient in response to greenhouse gas forcing. Assuming a steady linear relationship between African easterly waves and tropical cyclogenesis, this result suggests a future increase in Atlantic tropical cyclone frequency by 10% (20%) at the end of the 21st century under the RCP 4.5 (8.5) forcing scenario.J.P.D., K.B.K., and L.Z. Acknowledge support from the Strategic Environmental Research and Development Program (SERDP) (RC-2336).2018-03-0