Effects of Surface Flux Parameterization on the Numerically Simulated Intensity and Structure of Typhoon Morakot(2009)

The effects of surface flux parameterizations on tropical cyclone（TC） intensity and structure are investigated using the Advanced Research Weather Research and Forecasting（WRF-ARW） modeling system with high-resolution simulations of Typhoon Morakot（2009）.Numerical experiments are designed to simulate Typhoon Morakot（2009） with different formulations of surface exchange coefficients for enthalpy（C_K） and momentum（C_D） transfers,including those from recent observational studies based on in situ aircraft data collected in Atlantic hurricanes.The results show that the simulated intensity and structure are sensitive to C_K and C_D,but the simulated track is not.Consistent with previous studies,the simulated storm intensity is found to be more sensitive to the ratio of C_K/C_D than to C_K or C_D alone.The pressure-wind relationship is also found to be influenced by the exchange coefficients,consistent with recent numerical studies.This paper emphasizes the importance of C_D and C_K on TC structure simulations.The results suggest that C_D and C_K have a large impact on surface wind and flux distributions,boundary layer heights,the warm core,and precipitation.Compared to available observations,the experiment with observed C_D and C_K generally simulated better intensity and structure than the other experiments,especially over the ocean.The reasons for the structural differences among the experiments with different C_D and C_K setups are discussed in the context of TC dynamics and thermodynamics.

Effects of Precipitation on Sonic Anemometer Measurements of Turbulent Fluxes in the Atmospheric Surface Layer

Effects caused by precipitation on the measurements of three-dimensional sonic anemometer are analyzed based on a field observational experiment conducted in Maoming, Guangdong Province, China. Obvious fluctuations induced by precipitation are observed for the outputs of sonic anemometer-derived temperature and wind velocity components. A technique of turbulence spectra and cospectra normalized in the framework of similarity theory is utilized to validate the measured variables and calculated fluxes. It is found that the sensitivity of sonic anemometer-derived temperature to precipitation is significant, compared with that of the wind velocity components. The spectra of wind velocity and cospectra of momentum flux resemble the standard universal shape with the slopes of the spectra and cospectra at the inertial subrange, following the-2/3 and-4/3 power law, respectively, even under the condition of heavy rain. Contaminated by precipitation, however, the spectra of temperature and cospectra of sensible heat flux do not exhibit a universal shape and have obvious frequency loss at the inertial subrange. From the physical structure and working principle of sonic anemometer, a possible explanation is proposed to describe this difference, which is found to be related to the variations of precipitation particles. Corrections for errors of sonic anemometer-derived temperature under precipitation is needed, which is still under exploration.

Effect of Boundary Layer Latent Heating on MJO Simulations

A latent heating peak in the PBL was detected in a simulation by a global GCM that failed to reproduce Madden Julian Oscillation （MJO）. The latent heating peak in the PBL was generated by very shallow convection, which prevented moisture from being transported to the free troposphere. Large amount of moisture was therefore confined to the PBL, leading to a dry bias in the free atmosphere. Suffering from this dry bias, deep convection became lethargic, and MJO signals failed to occur. When the latent heating peak in the PBL was removed in another simulation, reasonable MJO signals, including the eastward propagation and the structure of its large-scale circulation, appeared. We therefore propose that the excessive latent heating peak in the PBL due to hyperactive shallow convection may be a reason for a lack of MJO signals in some simulations by other GCMs as well.

Impacts of a GCM's Resolution on MJO Simulation

Long-term integrations are conducted using the Spectral Atmospheric Model （referred to as SAMIL）, which was developed in the Laboratory for Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics （LASG） in the Institute of Atmospheric Physics （IAP）, with different resolutions to inves-tigate sensitivity of the Madden-Julian Oscillation （MJO） simulations to the model＇s resolution （horizontal and vertical）. Three resolutions of the model, R15L9, R42L9 and R42L26, with identical physical processes, all produced the basic observed features of the MJO, including the spatiotemporal space-time spectra and eastward propagation. No fundamental differences among these simulations were found. This indicates that the model resolution is not a determining factor for simulating the MJO. Detailed differences among these modeling results suggest, however, that model resolution can substantially affect the simulated MJO in certain aspects. For instance, at a lower horizontal resolution, high frequency disturbances were weaker and the structures of the simulated MJO were better defined to a certain extent. A higher vertical resolution led to a more realistic spatiotemporal spectrum and spatial distribution of MJO precipitation. Meanwhile, increasing the model＇s resolution improved simulation of the climatology. However, increasing the resolution should be based on improving the cumulus parameterization scheme.

An Assessment of a Nowcast/Forecast System for the Straits of Florida/Florida Current Regime

The Florida Current (FC) largely fills the Straits of Florida and is variable on a broad spectrum of time and space scales. Some portions of the variability are due to variable forcing by tides, winds, heating/cooling, and throughflow; other portions are due to intrinsic instabilities of the FC. To predict, as well as to better understand this complex regime, a nowcast/forecast system (East Florida Shelf Information System (EFSIS)) has been implemented and assessed (http://efsis. rsmas. miami. edu). EFSIS is based on an implementation of the Princeton Ocean Model (POM) with mesoscale - admitting resolution on a curvilinear grid. It is forced by a mesoscale numerical weather prediction system (called Eta) run operationally by the National Centers for Environmental Prediction (NCEP), eight tidal constituents from a global tidal model, and lateral boundary conditions from an operational global ocean prediction model, i.e., the Navy Coastal Ocean Model (NCOM).Real-time observations of coastal sea level, coastal sea surface temperature, coastal HF radar-derived surface current maps,and FC volume transport are used to verify and validate EFSIS. EFSIS is part of an evolving strategy for real-time predictive coastal ocean modeling methodology, and for fostering the understanding of the variability of the regime on several time and space scales. Here, some of the verification and validation results are provided, as well as diagnostic analyses of dynamical servations and numerical circulation models to yield a credible sequence of synoptic views of coastal ocean circulation for the first time.

“海洋性大陆”观测研究计划介绍及中国参与进展

1“海洋性大陆”观测研究计划介绍海洋性大陆（Maritime Continent,以下简称MC）是指由中南半岛、菲律宾群岛、印度尼西亚群岛、新几内亚岛等众多岛屿和中国南海及一系列浅海组成的区域（图1）,该地区地处太平洋、印度洋、亚洲、大洋洲的连接地带,是中国战略构想“海上丝绸之路”的必经之地。MC地区特殊的地理位置、复杂的海陆分布和地形状况,

外强迫对热带季节内振荡影响的模拟研究

应用经过修改的NCAR CCM3模式和CAM2模式进行的数值实验结果以及NCEP的GFS模式的输出结果讨论了海温等外强迫作用对热带季节内振荡的影响。结果表明,热带季节内振荡是热带大气固有的内部变率。它是由大气内部过程的相互作用决定的。但外强迫对热带季节内振荡的强度、传播方向等有明显的影响。当外强迫没有变化时,模式可以模拟出与观测近似的低频振荡。当作为外强迫的海温和太阳辐射有年内季节变化时,模式模拟的季节内振荡则明显减弱。当海温与辐射不仅有季节变化而且有年际变化时,模式模拟的季节内振荡会进一步减弱。具有长周期的外强迫还会削弱季节内振荡中东移波动的能量而增加静止波的强度。在与海洋模式耦合的状态下,模式不受来自海洋的外强迫影响,而是与海洋构成一个耦合系统,可以产生最强的季节内振荡。

Water Cooperation Priorities in the Lancang-Mekong River Basin Based on Cooperative Events Since the Mekong River Commission Establishment

The Lancang-Mekong River has attracted much attention from researchers, but the cooperation on water issues in this river basin has been limited, even after the establishment of the Mekong River Commission(MRC). Cooperation on water resources has been determined as one of the key priority areas in the Lancang-Mekong Cooperation Mechanism, but there are no details of targets. In order to establish the priorities of water cooperation under the mechanism, we adopted nine categories to classify the objectives of 87 water cooperation events based on the ‘Lancang-Mekong Water Cooperative Events Database' from 1995 to 2015. Based on the occurrence of cooperative events, cooperative objectives, cooperative scales, and approaches to cooperation, we conducted statistical, correlation, and text analyses. Our analyses indicated the following results: under the impact of economic conditions inside and outside the river basin, full cooperation appeared more difficult than bilateral and multilateral cooperation. Each of the partners adopted different preferences for cooperation targets. Cooperation with more definite objectives was easier to establish than cooperation with broader and more complex objectives. The potential objectives for water cooperation were navigation, hydropower, joint management, data sharing, flood control and water use. Because hydropower development is controversial, and because water cooperation is avoided by most existing regional cooperation mechanisms due to its complexity, we suggest the following priority areas for water cooperation in the Lancang-Mekong River Basin. 1) Navigation and flood control/drought relief are attractive objectives for all the riparian countries across the whole watershed. 2) Data sharing should be a priority for cooperation in the watershed due to its laying the foundation for the equitable and reasonable utilization of transboundary waters. 3) Hydropower is an objective best implemented mainly through bilateral cooperation, and on tributaries.

The critical role of Indian summer monsoon on the remote forcing between Indian and Northwest Pacific during El Nio decaying year

Recent studies have found a connection between Indian Ocean Basin Warming and the anomalous Northwest Pacific Anticyclone(ANPWA) during El Ni?o decaying year.This study focuses on the necessary condition for this connection by using observation and numerical simulation.The seasonal transition of the Indian Ocean sea surface wind is critical to the climatic effect of Indian Ocean Basin Warming.When the South Asian Summer Monsoon reaches its peak,the background wind becomes desirable for basin warming,which then affects the climate in the Northwest Pacific.Via the Kelvin waves and Ekman divergence,the wind anomalies exist in the lower atmosphere east of the Indian Ocean warm Sea Surface Temperature(SST) anomalies,and intensify and sustain the ANWPA throughout the El Nio decaying summer.This impact plays an important role in the inter-annual variability of the East Asian Summer Monsoon.

Notes,outline and divergence times of Basidiomycota

The Basidiomycota constitutes a major phylum of the kingdom Fungi and is second in species numbers to the Ascomycota.The present work provides an overview of all validly published,currently used basidiomycete genera to date in a single document.An outline of all genera of Basidiomycota is provided,which includes 1928 currently used genera names,with 1263 synonyms,which are distributed in 241 families,68 orders,18 classes and four subphyla.We provide brief notes for each accepted genus including information on classification,number of accepted species,type species,life mode,habitat,distribution,and sequence information.Furthermore,three phylogenetic analyses with combined LSU,SSU,5.8s,rpb1,rpb2,and ef1 datasets for the subphyla Agaricomycotina,Pucciniomycotina and Ustilaginomycotina are conducted,respectively.Divergence time estimates are provided to the family level with 632 species from 62 orders,168 families and 605 genera.Our study indicates that the divergence times of the subphyla in Basidiomycota are 406-430 Mya,classes are 211-383 Mya,and orders are 99-323 Mya,which are largely consistent with previous studies.In this study,all phylogenetically supported families were dated,with the families of Agaricomycotina diverging from 27-178 Mya,Pucciniomycotina from 85-222 Mya,and Ustilaginomycotina from 79-177 Mya.Divergence times as additional criterion in ranking provide additional evidence to resolve taxonomic problems in the Basidiomycota taxonomic system,and also provide a better understanding of their phylogeny and evolution.

厄尔尼诺衰亡年间南亚夏季风在印度洋对西北太平洋遥强迫中的作用

已有的大量研究给出了印度洋增暖的气候效应,特别是对于西北太平洋反气旋异常的影响.本文利用观测数据和耦合数值模式进一步分析了厄尔尼诺衰亡年印度洋增暖的气候效应,研究了印度洋海温异常与西北太平洋反气旋异常之间的遥强迫形成条件,提出印度洋背景风场的季节性转换对印度洋增暖效应的关键作用.结果表明,只有在有利的背景风场下,即南亚夏季季风完全爆发时,才更有利于印度洋增暖效应的充分体现.可能是由于Kelvin波-Ekman辐散机制,在北印度洋异常增暖所导致的大气热源异常的东侧低层大气中产生了明显的东风异常,这一东风异常对西北太平洋产生遥强迫,使西北太平洋的反气旋异常加强并维持到厄尔尼诺衰亡年夏季.这对于东亚夏季季风的年变率机制研究及预测有着重要意义.

A New Foraminiferal Bioindicator for Long-Term Heat Stress on Coral Reefs

Coral reefs are in terminal decline.For conservation to be effective,naturally depauperate reefs must be distinguished from those recently degraded by humans.Traditional reef monitoring is time consuming and lacks the longevity to make this distinction.Success in using foraminifera as bioindicators for reef health has hitherto levered their response to nutrients.Because ocean heat waves are the dominant driver of coral bleaching and death,there is compelling motivation to develop new foraminiferal bioindicators that inform on temperature stress over meaningful timescales.This study focuses on identifying which foraminifera respond systematically to the temperature stress that kills corals.Statistical models were used to compare endosymbiont-bearing foraminiferal families,collected along a heat-stress gradient spanning the Solomon Islands and New Caledonia,to live coral cover at the same sites.Results indicate that Amphisteginidae foraminifera and coral cover show a significant decline in abundance as heat stress increases along the transect sites.Furthermore,ocean productivity and salinity,both recognized environmental influences on foraminifera,are shown to be subordinate to temperature in their sway of this ecological patterning.These findings indicate the potential for using foraminifera to develop new indices capable of quantifying long-term thermal impacts on reefs.