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Downscaling Seasonal Precipitation Forecasts over East Africa with Deep Convolutional Neural Networks

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Advances in Atmospheric Sciences 2024年第3期41卷 449-464页

作者： Temesgen Gebremariam ASFAW jing-jia LUO Institute for Climate and Application Research(ICAR)/CIC-FEMD/KLME/ILCEC Nanjing University of Information Science and TechnologyNanjing 210044China Institute of Geophysics Space Science and Astronomy Addis Ababa UniversityAddis Ababa 1176Ethiopia

This study assesses the suitability of convolutional neural networks(CNNs) for downscaling precipitation over East Africa in the context of seasonal forecasting. To achieve this, we design a set of experiments that compare different CNN configurations and deployed the best-performing architecture to downscale one-month lead seasonal forecasts of June–July–August–September(JJAS) precipitation from the Nanjing University of Information Science and Technology Climate Forecast System version 1.0(NUIST-CFS1.0) for 1982–2020. We also perform hyper-parameter optimization and introduce predictors over a larger area to include information about the main large-scale circulations that drive precipitation over the East Africa region, which improves the downscaling results. Finally, we validate the raw model and downscaled forecasts in terms of both deterministic and probabilistic verification metrics, as well as their ability to reproduce the observed precipitation extreme and spell indicator indices. The results show that the CNN-based downscaling consistently improves the raw model forecasts, with lower bias and more accurate representations of the observed mean and extreme precipitation spatial patterns. Besides, CNN-based downscaling yields a much more accurate forecast of extreme and spell indicators and reduces the significant relative biases exhibited by the raw model predictions. Moreover, our results show that CNN-based downscaling yields better skill scores than the raw model forecasts over most portions of East Africa. The results demonstrate the potential usefulness of CNN in downscaling seasonal precipitation predictions over East Africa,particularly in providing improved forecast products which are essential for end users.

关键词： East Africa seasonal precipitation forecasting downscaling deep learning convolutional neural networks(CNNs)

Upper Bounds for the Spectral Radii of Nonnegative Tensors

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Journal of the Operations Research Society of China 2017年第1期5卷 83-98页

作者： jing-jing jia Qing-Zhi Yang School of Mathematical Sciences and LPMC Nankai UniversityTianjin 300071China School of Mathematics and Statistics Kashi UniversityKashi 844006XinjiangChina

In this paper,we present several sharper upper bounds for the M-spectral radius and Z-spectral radius based on the eigenvalues of some unfolding matrices of nonnegative ***,we show that these bounds could be tight for some special *** a general nonnegative tensor which can be transformed into a matrix,we prove the maximal singular value of this matrix is an upper bound of its *** examples are provided to show these proposed bounds greatly improve some existing ones.

关键词： Nonnegative tensor M-eigenvalue Z-eigenvalue Weakly symmetric Spectral radius

The Forecast Skills and Predictability Sources of Marine Heatwaves in the NUIST-CFS1.0 Hindcasts

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Advances in Atmospheric Sciences 2024年第8期41卷 1589-1600页

作者： jing MA Haiming XU Changming DONG jing-jia LUO Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/KLME/ILCEC/Institute of Climate and Application Research(ICAR) Nanjing University of Information Science and TechnologyNanjingJiangsu 210044China

Using monthly observations and ensemble hindcasts of the Nanjing University of Information Science and Technology Climate Forecast System(NUIST-CFS1.0) for the period 1983–2020, this study investigates the forecast skill of marine heatwaves(MHWs) over the globe and the predictability sources of the MHWs over the tropical oceans. The MHW forecasts are demonstrated to be skillful on seasonal-annual time scales, particularly in tropical oceans. The forecast skill of the MHWs over the tropical Pacific Ocean(TPO) remains high at lead times of 1–24 months, indicating a forecast better than random chance for up to two years. The forecast skill is subject to the spring predictability barrier of El Nino-Southern Oscillation(ENSO). The forecast skills for the MHWs over the tropical Indian Ocean(TIO), tropical Atlantic Ocean(TAO), and tropical Northwest Pacific(NWP) are lower than that in the TPO. A reliable forecast at lead times of up to two years is shown over the TIO, while a shorter reliable forecast window(less than 17 months) occurs for the TAO and ***, the forecast skills for the TIO, TAO, and NWP are seasonally dependent. Higher skills for the TIO and TAO appear in boreal spring, while a greater skill for the NWP emerges in late summer-early autumn. Further analyses suggest that ENSO serves as a critical source of predictability for MHWs over the TIO and TAO in spring and MHWs over the NWP in summer.

关键词： marine heatwaves NUIST-CFS1.0 hindcasts forecast skill predictability source ENSO

THE GLOBAL WELL-POSEDNESS OF SOLUTIONS TO COMPRESSIBLE ISENTROPIC TWO-FLUID MAGNETOHYDRODYNAMICS IN A STRIP DOMAIN

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Acta Mathematica Scientia 2024年第5期44卷 1997-2018页

作者： Zefu FENG jing jia School of Mathematical Sciences Chongqing Normal UniversityChongqing401331China

In this paper,we consider a model of compressible isentropic two-fluid magneto-hydrodynamics without resistivity in a strip domain in three dimensional *** exploiting the two-tier energy method developed in[Anal PDE,2013,6:1429–1533],we prove the global well-posedness of the governing model around a uniform magnetic field which is non-parallel to the horizontal ***,we show that the solution converges to the steady state at an almost exponential rate as time goes to *** to the work of Tan and Wang[SIAM J Math Anal,2018,50:1432–1470],we need to overcome the difficulties caused by particles.

关键词： two-fluid magnetohydrodynamics global well-posedness compressiblility

Seasonal Forecasts of Precipitation during the First Rainy Season in South China Based on NUIST-CFS1.0

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Advances in Atmospheric Sciences 2023年第10期40卷 1895-1910页

作者： Sinong LI Huiping YAN jing-jia LUO Institute for Climate and Application Research(ICAR)/CIC-FEMD/KLME/ILCEC Nanjing University of Information Science and TechnologyNanjing 210044China

Current dynamical models experience great difficulties providing reliable seasonal forecasts of regional/local rainfall in South *** study evaluates seasonal forecast skill for precipitation in the first rainy season(FRS,i.e.,April–June)over South China from 1982 to 2020 based on the global real-time Climate Forecast System of Nanjing University of Information Science and Technology(NUIST-CFS1.0,previously known as SINTEX-F).The potential predictability and the practical forecast skill of NUIST-CFS1.0 for FRS precipitation remain low in *** NUIST-CFS1.0 still performs better than the average of nine international models in terms of correlation coefficient skill in predicting the interannual precipitation anomaly and its related circulation ***-CFS1.0 captures the anomalous Philippines anticyclone,which transports moisture and heat northward to South China,favoring more precipitation in South China during the *** examining the correlations between sea surface temperature(SST)and FRS precipitation and the Philippines anticyclone,we find that the model reasonably captures SST-associated precipitation and circulation anomalies,which partly explains the predictability of FRS precipitation.A dynamical downscaling model with 30-km resolution forced by the large-scale circulations of the NUIST-CFS1.0 predictions could improve forecasts of the climatological states and extreme precipitation *** results also reveal interesting interdecadal changes in the predictive skill for FRS precipitation in South China based on the NUIST-CFS1.0 *** results help improve the understanding and forecasts for FRS precipitation in South China.

关键词： seasonal forecast of precipitation first rainy season in South China global climate model prediction

Prediction of Seasonal Tropical Cyclone Activity in the NUIST-CFS1.0 Forecast System

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Advances in Atmospheric Sciences 2023年第7期40卷 1309-1325页

作者： Ke PENG jing-jia LUO Yan LIU Key Laboratory of Meteorological Disaster Ministry of Education(KLME)/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)/Institute for Climate and Application Research(ICAR)Nanjing University of Information Science and TechnologyNanjing 210044China School of Atmospheric Sciences and Key Laboratory of Mesoscale Severe Weather/Ministry of EducationNanjing UniversityNanjing 210023China

Prediction skill for the seasonal tropical cyclone(TC)activity in the Northern Hemisphere is investigated using the coupled climate forecast system(version 1.0)of Nanjing University of Information Science and Technology(NUISTCFS1.0).This assessment is based on the seven-month(May to November)hindcasts consisting of nine ensemble members during 1982–*** predictions are compared with the Japanese 55-year Reanalysis and observed tropical storms in the Northern *** results show that the overall distributions of the TC genesis and track densities in model hindcasts agree well with the observations,although the seasonal mean TC frequency and accumulated cyclone energy(ACE)are underestimated in all basins due to the low resolution(T106)of the atmospheric component in the ***-CFS1.0 closely predicts the interannual variations of TC frequency and ACE in the North Atlantic(NA)and eastern North Pacific(ENP),which have a good relationship with indexes based on the sea surface *** the western North Pacific(WNP),NUIST-CFS1.0 can closely capture ACE,which is significantly correlated with the El Ni?o–Southern Oscillation(ENSO),while it has difficulty forecasting the interannual variation of TC frequency in this *** the WNP is further divided into eastern and western subregions,the model displays improved TC activity forecasting ***,it is found that biases in predicted TC genesis locations lead to inaccurately represented TC–environment relationships,which may affect the capability of the model in reproducing the interannual variations of TC activity.

关键词： seasonal tropical cyclone activity interannual variation global ocean-atmosphere coupled forecast system

Seasonal Predictions of Summer Precipitation in the Middle-lower Reaches of the Yangtze River with Global and Regional Models Based on NUIST-CFS1.0

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Advances in Atmospheric Sciences 2022年第9期39卷 1561-1578页

作者： Wushan YING Huiping YAN jing-jia LUO Institute for Climate and Application Research(ICAR)/ILCEC Key Laboratory of Meteorological DisasterNanjing University of Information Science and TechnologyNanjing 210044China

Accurate prediction of the summer precipitation over the middle and lower reaches of the Yangtze River(MLYR)is of urgent demand for the local economic and societal *** study assesses the seasonal forecast skill in predicting summer precipitation over the MLYR region based on the global Climate Forecast System of Nanjing University of Information Science and Technology(NUIST-CFS1.0,previously SINTEX-F).The results show that the model can provide moderate skill in predicting the interannual variations of the MLYR rainbands,initialized from 1 *** addition,the nine-member ensemble mean can realistically reproduce the links between the MLYR precipitation and tropical sea surface temperature(SST)anomalies,but the individual members show great discrepancies,indicating large uncertainty in the ***,the NUIST-CFS1.0 can predict five of the seven extreme summer precipitation anomalies over the MLYR during 1982-2020,albeit with underestimated *** Weather Forecast and Research(WRF)downscaling hindcast experiments with a finer resolution of 30 km,which are forced by the large-scale information of the NUIST-CFS1.0 predictions with a spectral nudging method,display improved predictions of the extreme summer precipitation anomalies to some ***,the performance of the downscaling predictions is highly dependent on the global model forecast skill,suggesting that further improvements on both the global and regional climate models are needed.

关键词： seasonal forecast summer precipitation global climate model WRF downscaling

Myotis bat STING attenuates aging-related inflammation in female mice

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Zoological Research 2024年第5期45卷 961-971页

作者： Xi Wang jing-Kun jia Qi Wang jing-Wen Gong Ang Li jia Su Peng Zhou Wuhan Institute of Virology Chinese Academy of SciencesWuhanHubei 430071China Guangzhou National Laboratory Guangzhou International Bio IslandGuangzhouGuangdong 510005China University of Chinese Academy of Sciences Beijing 100000China State Key Laboratory of Respiratory Disease First Affiliated Hospital of Guangzhou Medical SchoolGuangzhouGuangdong 510005China

Bats,notable as the only flying mammals,serve as natural reservoir hosts for various highly pathogenic viruses in humans(e.g.,SARS-CoV and Ebola virus).Furthermore,bats exhibit an unparalleled longevity among mammals relative to their size,particularly the Myotis bats,which can live up to 40 ***,the mechanisms underlying these distinctive traits remain incompletely *** our prior research,we demonstrated that bats exhibit dampened STING-interferon activation,potentially conferring upon them the capacity to mitigate virus-or aging-induced *** substantiate this hypothesis,we established the first in vivo bat-mouse model for aging studies by integrating Myotis davidii bat STING(MdSTING)into the mouse *** monitored the genotypes of these mice and performed a longitudinal comparative transcriptomic analysis on MdSTING and wild-type mice over a 3-year aging *** transcriptomic analysis indicated a reduction in aging-related inflammation in female MdSTING mice,as evidenced by significantly lower levels of pro-inflammatory cytokines and chemokines,immunopathology,and neutrophil recruitment in aged female MdSTING mice compared to aged wild-type mice in *** results indicated that MdSTING knock-in attenuates the aging-related inflammatory response and may also improve the healthspan in mice in a sex-dependent *** the underlying mechanism awaits further study,this research has critical implications for bat longevity research,potentially contributing to our comprehension of healthy aging in humans.

关键词： Bat STING Longevity Aging-related inflammation Virus reservoir host

MicroRNAs in colorectal cancer as markers and targets:Recent advances

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World Journal of Gastroenterology 2014年第15期20卷 4288-4299页

作者： jing-jia Ye jiang Cao Clinical Research Center The Second Affiliated HospitalZhejiang University School of Medicine

MicroRNAs are evolutionarily conserved small noncoding RNA molecules encoded by eukaryotic genomic DNA,and function in post-transcriptional regulation of gene expression via base-pairing with complementary sequences in target mRNAs,resulting in translational repression or degradation of target *** represent one of the major types of epigenetic modification and play important roles in all aspects of cellular *** expression of microRNAs has been found in various human diseases including *** efforts have been made to discover the characteristic microRNA expression profiles,to understand the roles of aberrantly expressed microRNAs and underlying mechanisms in different *** the application of DNA microarray,real-time quantitative polymerase chain reaction and other molecular biology techniques,increasing evidence has been accumulated which reveal that aberrant microRNAs can be detected not only intracellularly within the cancer cells,but also extracellularly in plasma of patients,postulating the potential of aberrant microRNAs as promising diagnostic/prognostic markers and attracting therapeutic *** review is intended to provide the most recent advances in microRNA studies in one of the most common cancers,colorectal cancer,especially the identification of those specifically altered microRNAs in colorectal cancer,validation for their relevance to clinical pathological parameters of patients,functional analyses and potential applications of these microRNAs.

关键词： MicroRNA Epigenetic modification Colorectal cancer Marker Therapy