The variability of observed tropical cyclone (TC) activity (i.e., genesis, track, and landfall) in the western North Pacific (WNP) is examined in relation to the various categories of the Madden–Julian oscillation (MJO) during summer (June–September) for the period 1979–2004. The MJO categories are defined based on the empirical orthogonal function analysis of outgoing longwave radiation data. The number of TCs increases when the MJO-related convection center is located in the WNP. The axis of a preferable genesis region systematically shifts like a seesaw in response to changes in the large-scale environments associated with both the eastward and northward propagation of the MJO and the intraseasonal variability of the WNP subtropical high. Furthermore, the authors show that the density of TC tracks in each MJO category depends on the systematic shift in the main genesis regions at first order. Also, the shift is affected by the prevailing large-scale steering flows in each MJO category. When the MJO-related convection center is found in the equatorial Indian Ocean (the tropical WNP), a dense area of tracks migrates eastward (westward). The effects of extreme ENSO events and the variations occurring during ENSO neutral years are also examined. A statistical analysis of TC landfalls by MJO category is applied in seven selected subareas: the Philippines, Vietnam, South China, Taiwan, East China, Korea, and Japan. While a robust and significant modulation in the number of TC landfalls is observed in south China, Korea, and Japan, the modulation is marginal in the remaining four subareas.

Flash droughts and their physical processes have received increasing attention in recent years due to concerns about the potential of flash droughts to affect water resources and ecosystems. Yet to date, the response of ecosystems during flash drought events, particularly on a large scale, and the determinants of the ecosystem responses to flash droughts have been underexplored. Here we analyse temporal variations in vegetation anomalies during flash drought events at a global scale between 2001 and 2020 using observation-based leaf area index, gross primary productivity, and solar-induced chlorophyll fluorescence data. We identify divergent ecosystem responses in terms of the timing and intensification of drought-induced vegetation stress across different regions around the world. Furthermore, we find that these regional differences are largely modulated by background climate and vegetation conditions, rather than meteorological conditions, with ecosystems being subjected to more rapidly developing and greater degrees of vegetation stress in arid and short vegetation-dominated regions as compared to humid forests. Our results highlight the spatially heterogeneous ecological impacts of flash droughts, implying the need to comprehensively integrate aspects of both atmospheric and bioclimatic properties in flash drought monitoring and forecasting systems to improve our ability to track their evolution and impacts.

The conventional Lorenz-Mie formalism is extended to the case for a coated sphere embedded in an absorbing medium. The apparent and inherent scattering cross sections of a particle, derived from the far field and near field, respectively, are different if the host medium is absorptive. The effect of absorption within the host medium on the phase-matrix elements associated with polarization depends on the dielectric properties of the scattering particle. For the specific cases of a soot particle coated with a water layer and an ice sphere containing an air bubble, the phase-matrix elements -P ₁₂/P ₁₁ and P ₃₃/P ₁₁ are unique if the shell is thin. The radiative transfer equation for a multidisperse particle system embedded within an absorbing medium is discussed. Conventional multiple-scattering computational algorithms can be applied if scaled apparent single-scattering properties are applied.