Understanding urban impacts on hydrometeorological processes is becoming an emergent issue under the context of soaring urban population globally (UNPD, 2019). This is accompanied by ample evidence of elevated extreme rainfall and flood hazards under a changing climate, with urban areas most vulnerable (IPCC, 2021). Empirical and modeling analyses reveal notable urban-induced rainfall anomalies over a collection of worldwide cities, including the pioneering

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Chaetospirolactone (1), a novel spiro-lactone bearing a rare 1-oxaspiro [4.4] non-7-ene-2,6-dione skeleton, and orsellide F (2), together with six known compounds (3-8), were isolated from an endophytic fungus Chaetomium sp. NF00754. Their structures were determined by interpretation of spectroscopic data. The absolute configurations of 1 and 2 were established by analysis of single X-ray crystallographic data and CD spectra. Compounds 3, 4, and 6 showed moderate acetylcholinesterase inhibitory activity with IC values of 7.34, 5.19, and 7.67 μM, respectively.

The nexus between atmospheric moisture transport and basin‐scale flood response is still lacking over the Third Pole (TP) region, despite projected increases in extreme rainfall under a changing climate. Based on long‐term daily streamflow observations, we show that peaks‐over‐threshold floods over the Yarlung Zangbo River (YZR) basin show two temporal clusters, that is, July and late August, with the flood magnitudes of the second cluster larger than the first by 20%. These floods are resultant from a mixture of flood‐producing storms with contrasting storm motion and moisture transport pathways. A suite of coupled atmospheric‐hydrological modeling experiments further quantify the impacts of different moisture transport pathways on the space‐time rainfall structure and flood response. A 50% reduction of upper level moisture transport (i.e., through the upslope of the Himalayas) leads to decreased flood peak magnitudes by 30% at the basin outlet for the August 1998 floods over the YZR basin. Upper‐level moisture transport is associated with the notable low pressure over the central‐east India and westward extension of West Pacific Subtropical High that enhances convergence of water vapor fluxes from Bay of Bengal toward TP. The magnitude of impact can potentially alter the seasonal clustering of high‐flow events over TP. Our analyses contribute to improved characterization of flood risk over TP, and advances in flood frequency hydrology.