Projected changes of wintertime synoptic‐scale transient eddy activities in the East Asian eddy‐driven jet from CMIP5 experiments

The wintertime East Asian eddy‐driven jet (EAEJ) responding to climate change in the 21st century is studied using model outputs from the Coupled Model Intercomparison Project phase 5 (CMIP5). Compared to the location displacement in oceanic eddy‐driven jets, the magnitude change of synoptic‐scale transient eddy activities, measured by eddy kinetic energy (EKE), is a more striking feature in EAEJ. An intensified EKE is projected unanimously by CMIP5 models, suggesting that potential strong winter storm events are likely to happen in East Asian midlatitude in a warming climate. The future change of EKE in EAEJ can be understood in terms of growing baroclinicity wave. The upper level EKE is highly correlated to the low‐level static stability, Brunt‐Väisälä frequency (BVF). CMIP5 models generally project an intensified upper evel EKE with a reduced low‐level BVF (ΔEKE ∝ −ΔBVF). Meanwhile, the enhancement of EKE is also constrained by its historical state (ΔEKE ∝ −EKE). Intermodel variabilities among CMIP5 models reveal a similar but weaker relationship between ΔBVF (or EKE) and ΔEKE, indicating relatively large model diversities and independencies among CMIP5 models.Key PointsThe East Asian eddy‐driven jet will be intensified in a warming climateThe enhancement is related to the surface stability and the historical stateCMIP5 models exhibit large model diversities and independenciesPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/113168/1/grl53203.pd

Improving the lake scheme within a coupled WRF‐lake model in the Laurentian Great Lakes

In this study, a one‐dimensional (1‐D) thermal diffusion lake model within the Weather Research and Forecasting (WRF) model was investigated for the Laurentian Great Lakes. In the default 10‐layer lake model, the albedos of water and ice are specified with constant values, 0.08 and 0.6, respectively, ignoring shortwave partitioning and zenith angle, ice melting, and snow effect. Some modifications, including a dynamic lake surface albedo, tuned vertical diffusivities, and a sophisticated treatment of snow cover over lake ice, have been added to the lake model. A set of comparison experiments have been carried out to evaluate the performances of different lake schemes in the coupled WRF‐lake modeling system. Results show that the 1‐D lake model is able to capture the seasonal variability of lake surface temperature (LST) and lake ice coverage (LIC). However, it produces an early warming and quick cooling of LST in deep lakes, and excessive and early persistent LIC in all lakes. Increasing vertical diffusivity can reduce the bias in the 1‐D lake but only in a limited way. After incorporating a sophisticated treatment of lake surface albedo, the new lake model produces a more reasonable LST and LIC than the default lake model, indicating that the processes of ice melting and snow accumulation are important to simulate lake ice in the Great Lakes. Even though substantial efforts have been devoted to improving the 1‐D lake model, it still remains considerably challenging to adequately capture the full dynamics and thermodynamics in deep lakes.Key PointsA dynamic lake surface albedo scheme is added to the lake modelThe new lake model produces a more reasonable LST and LIC than the default lake modelIce melting and snow accumulation are important to simulating lake ice in the Great LakesPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135995/1/jame20346_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135995/2/jame20346.pd

Coupling Coordination Analysis of County Tourism Development and Multidimensional Poverty Based on Nighttime Light Data

In China, tourism development is a crucial approach to poverty alleviation. With the consolidation of poverty alleviation achievements and the promotion of rural revitalization, it is of great significance to explore the relationship between tourism development and poverty alleviation from the perspective of multidimensional poverty. Therefore, this study took 28 key assistance counties for rural revitalization in the Sichuan–Chongqing region (hereinafter referred to as “key counties”) as the research objects, introduced NPP-VIIRS nighttime light (NTL) data, and a coupling coordination degree (CCD) model to explore the coordination relationship and mechanism between them. The results showed that from 2015 to 2020, the tourism development index (TDI) and estimated comprehensive development index (ECDI) of the key counties increased by 112.57% and 115.12%, respectively. In addition, the spatial differences in tourism development and multidimensional poverty both showed a narrowing trend. According to the results of the CCD model, the key counties basically faced coordination obstacles in the early stage, which were mainly transformed into reluctant coordination and moderate coordination in the later stage. This indicated that tourism poverty alleviation showed a coordinated development trend overall. However, the study also found that there may not be synchronicity between tourism development and poverty alleviation and analyzed the mechanism of their interaction. Overall, the study confirmed the positive impact of tourism development on alleviating multidimensional poverty. In addition, the study found that measuring multidimensional poverty based on NTL data has a high accuracy and can provide support for poverty research. These research results have an important reference value for China to carry out sustainable tourism poverty alleviation and comprehensively promote rural revitalization

Turbulent Heat Fluxes during an Extreme Lake-Effect Snow Event

Proper modeling of the turbulent heat fluxes over lakes is critical for accurate predictions of lake-effect snowfall (LES). However, model evaluation of such a process has not been possible because of the lack of direct flux measurements over lakes. The authors conducted the first-ever comparison of the turbulent latent and sensible heat fluxes between state-of-the-art numerical models and direct flux measurements over Lake Erie, focusing on a record LES event in southwest New York in November 2014. The model suite consisted of numerical models that were operationally and experimentally used to provide nowcasts and forecasts of weather and lake conditions. The models captured the rise of the observed turbulent heat fluxes, while the peak values varied significantly. This variation resulted in an increased spread of simulated lake temperature and cumulative evaporation as the representation of the model uncertainty. The water budget analysis of the atmospheric model results showed that the majority of the moisture during this event came from lake evaporation rather than a larger synoptic system. The unstructured-grid Finite-Volume Community Ocean Model (FVCOM) simulations, especially those using the Coupled Ocean–Atmosphere Response Experiment (COARE)-Met Flux algorithm, presented better agreement with the observed fluxes likely due to the model’s capability in representing the detailed spatial patterns of the turbulent heat fluxes and the COARE algorithm’s more realistic treatment of the surface boundary layer than those in the other models.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/192644/1/hydr-jhm-d-17-0062_1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/192644/2/10_1175_jhm-d-17-0062_s1.docxDescription of hydr-jhm-d-17-0062_1.pdf : Main article in PDF formDescription of 10_1175_jhm-d-17-0062_s1.docx : Supplemental Materia