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Article: Decadal change of extreme consecutive dry days in spring over the middle and lower reaches of the Yangtze River around the early 2000s: The synergistic effect of mega-El Niño/Southern Oscillation, Atlantic Multidecadal Oscillation, and Arctic sea ice

Zeng, Zixuan / Sun, Jianqi

Atmospheric research. 2022 Mar., v. 266

2022

Abstract: Base on daily station precipitation data from 1960 to 2019, the variability of extreme consecutive dry days (extreme-CDDs) over the middle and lower reaches of the Yangtze River (MLRYR) during spring sowing time (March–April) is investigated. It is found ...

Abstract	Base on daily station precipitation data from 1960 to 2019, the variability of extreme consecutive dry days (extreme-CDDs) over the middle and lower reaches of the Yangtze River (MLRYR) during spring sowing time (March–April) is investigated. It is found that the extreme-CDDs over MLRYR experienced a significant decadal increase around the early 2000s. Associated with this decadal change, the Mongolian high and western North Pacific anticyclone (WNPA) are significantly intensified and weakened, respectively. The intensified Mongolian high and weakened WNPA lead to anomalous northerlies and water vapor divergence over MLRYR, providing favorable atmospheric conditions for more extreme-CDDs over the region. Further mechanism analyses suggest that the transition of mega-El Niño/Southern Oscillation (mega-ENSO) from negative-phase to positive-phase contributes to the decadal weakening of WNPA. And the phase transition of Atlantic Multidecadal Oscillation (AMO) and decadal decrease of sea ice over the Barents Sea lead to intensified Mongolian high through exciting atmospheric wave train. Multiple linear regression shows that there could be a synergistic role of mega-ENSO, AMO, and sea ice over the Barents Sea in the decadal change in extreme-CDDs over MLRYR around the early 2000s. Analysis on the simulation of 14 models in the Atmospheric Model Intercomparison Project (AMIP) experiment from phase 6 of the Coupled Model Intercomparison Project (CMIP6) shows that the models can reproduce the observed decadal intensification of the Mongolian high and weakening of WNPA around the early 2000s, which indicates the contribution of mega-ENSO, AMO, and sea ice over the Barents Sea to the decadal changes in Mongolian high, WNPA and extreme-CDDs over MLRYR.
Keywords	models ; phase transition ; regression analysis ; research ; sea ice ; spring ; synergism ; water vapor ; Arctic Ocean ; Barents Sea ; Yangtze River
Language	English
Dates of publication	2022-03
Publishing place	Elsevier B.V.
Document type	Article
ISSN	0169-8095
DOI	10.1016/j.atmosres.2021.105936
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Seasonal prediction of summer extreme precipitation frequencies over Southwest China based on machine learning

Nie, Yanbo / Sun, Jianqi / Ma, Jiehua

Atmospheric Research. 2023 Aug. 05, p.106947-

2023 , Page(s) 106947–

Abstract: It is challenging to predict extreme precipitation over regions with complex terrain, such as Southwest China (SWC). This study develops a statistical seasonal prediction scheme for summer extreme precipitation frequencies (EPFs) over SWC. In this scheme, ...

Abstract	It is challenging to predict extreme precipitation over regions with complex terrain, such as Southwest China (SWC). This study develops a statistical seasonal prediction scheme for summer extreme precipitation frequencies (EPFs) over SWC. In this scheme, the year-to-year increment method is first applied to the SWC summer EPFs and boundary forcings in preceding seasons. The first six leading modes of SWC summer EPFs are extracted by empirical orthogonal function (EOF) decomposition. The relationships between the six modes and preceding boundary forcings are investigated. According to these relationships, physics-based predictors for the principal components (PCs) of the modes are selected. The mechanisms by which the predictors influence the first two modes are analyzed as examples in this study. Two machine learning (ML) models, random forest and extreme gradient boosting, are trained using the data during 1980–2011. The ML models that perform best for each PC on the training data are used to be independently tested on data during 2012–2021. The predicted EPF patterns can be reconstructed by predicted PCs and observed EOFs. Prediction results indicate that the optimal ML models can well capture the variations in the six modes and SWC EPF spatial patterns and outperform the traditional stepwise regression models. The prediction skills for SWC summer EPF anomaly patterns show year-to-year variations which depend on the prediction results of the PCs. This scheme may help the seasonal predictions of SWC summer EPFs.
Keywords	landscapes ; prediction ; research ; summer ; China ; Southwest China ; Seasonal prediction ; Extreme precipitation ; Machine learning ; Year-to-year increment
Language	English
Dates of publication	2023-0805
Publishing place	Elsevier B.V.
Document type	Article ; Online
Note	Pre-press version
ISSN	0169-8095
DOI	10.1016/j.atmosres.2023.106947
Database	NAL-Catalogue (AGRICOLA)

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Article: A skillful prediction scheme for April precipitation over central East China

Han, Shuangze / Sun, Jianqi

Atmospheric research. 2021 Oct. 15, v. 261

2021

Abstract: Central East China (30°N–42°N, 105°E–122°E), around the lower and middle reaches of the Yangtze River valley to north China, is one of the main agricultural bases over East Asia. Spring precipitation can significantly influence the regional agricultural ... ...

Abstract	Central East China (30°N–42°N, 105°E–122°E), around the lower and middle reaches of the Yangtze River valley to north China, is one of the main agricultural bases over East Asia. Spring precipitation can significantly influence the regional agricultural activity and production, such as the crop planting and winter wheat growing over the region. Here, we find that different from the March and May precipitation over central East China, the April precipitation there shows relatively weak relationships with the preceding El Niño-Southern Oscillation (ENSO) and Indian Ocean basin mode (IOB) which are usually used as the prediction signals. Therefore, in this study, from the perspective of the prediction, we identify two predictors in the preceding months for the variability in the April precipitation over central East China: (1) the sea surface temperature (SST) over the subtropical North Atlantic in January and (2) the snow cover around the region to the east of Lake Baikal in March. The anomalous SST signal shows a good persistence from January to April, and further stimulates a wave train propagating from the subtropical North Atlantic eastward to East Asia during April, which could contribute to an anomalous East Asian trough and thereby the precipitation anomalies over central East China. The anomalous snow cover signal in March also tends to persist to the following April, and the associated anomalous cooling/warming could exert an impact on the East Asian trough, consequently influencing the April precipitation over central East China. Based on the two predictors, we establish a statistical prediction scheme and further evaluate its predictive skills. The results suggest the potential of the scheme for the prediction of the April central East China precipitation.
Keywords	basins ; cooling ; prediction ; research ; river valleys ; snowpack ; surface water temperature ; winter wheat ; China ; Indian Ocean ; Lake Baikal ; Yangtze River
Language	English
Dates of publication	2021-1015
Publishing place	Elsevier B.V.
Document type	Article
ISSN	0169-8095
DOI	10.1016/j.atmosres.2021.105737
Database	NAL-Catalogue (AGRICOLA)

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Article: Impacts of North Atlantic sea surface temperature on the predominant modes of spring precipitation monthly evolution over Northeast China

Zhang, Mengqi / Sun, Jianqi / Gao, Yongqi

Climate dynamics. 2022 Mar., v. 58, no. 5-6

2022

Abstract: Northeast China (NEC) is an important crop production base in East Asia. The monthly evolution of precipitation during spring sowing from April to May is of significance for agricultural activity and production over NEC. This study first investigates the ...

Abstract	Northeast China (NEC) is an important crop production base in East Asia. The monthly evolution of precipitation during spring sowing from April to May is of significance for agricultural activity and production over NEC. This study first investigates the predominant modes of April-to-May precipitation evolution over NEC and then explores their connections with North Atlantic sea surface temperature (SST) anomalies during 1979–2016. The first mode obtained using a multivariate empirical orthogonal function (MV-EOF1) shows an out-of-phase change in NEC precipitation anomalies from April to May, but the second mode (MV-EOF2) shows an in-phase change. Further analysis indicates that SST variability over mid-latitude North Atlantic (MNA) is related to MV-EOF1 by exciting a wave train from MNA to Eurasia. The wave train position is located more westward in May relative to April, leading to reverse atmospheric circulation and precipitation anomalies over NEC between April and May. The changes in position of circulations may be related to the westward shift of the North Atlantic storm track from April to May. MV-EOF2 is related to SST variability over northern tropical Atlantic (NTA). In April, NTA SST anomalies impact NEC precipitation through mid-latitude Eurasian wave train and Walker-like circulation anomalies between the Atlantic and Pacific Oceans. In May, the mid-latitude pathway is effective; however, the tropical pathway is significantly weakened, which may be related to the weakened intensity of NTA SST-induced tropical diabatic heating. Numerical simulations can reproduce the linkage between the North Atlantic SSTs and the pronounced atmospheric circulation anomalies in the observation, further confirming the impacts of North Atlantic SSTs on NEC April-to-May precipitation evolution.
Keywords	atmospheric circulation ; climate ; crop production ; dynamics ; evolution ; heat ; latitude ; spring ; storms ; surface water temperature ; China ; Eurasia
Language	English
Dates of publication	2022-03
Size	p. 1383-1401.
Publishing place	Springer Berlin Heidelberg
Document type	Article
ZDB-ID	1471747-5
ISSN	1432-0894 ; 0930-7575
ISSN (online)	1432-0894
ISSN	0930-7575
DOI	10.1007/s00382-021-05966-8
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Study on the Thermogravimetric Kinetics of Dehydrated Sewage Sludge Regulated by Cationic Polyacrylamide and Sawdust.

Yang, Kai / Sun, Jianqi / Liu, Hongning / Yang, Weichao / Dong, Lei

Polymers

2023 Volume 15, Issue 10

Abstract: With the continuous increase in sewage-sludge production worldwide, the pyrolytic disposal of sludge has received great attention. To build knowledge on the kinetics of pyrolysis, first, sludge was regulated using appropriate amounts of cationic ... ...

Abstract	With the continuous increase in sewage-sludge production worldwide, the pyrolytic disposal of sludge has received great attention. To build knowledge on the kinetics of pyrolysis, first, sludge was regulated using appropriate amounts of cationic polyacrylamide (CPAM) and sawdust to study their enhancing effect on dehydration. Due to the effects of the charge neutralization and skeleton hydrophobicity, a certain dose of CPAM and sawdust reduced the sludge's moisture content from 80.3% to 65.7%. Next, the pyrolysis characteristics of the dehydrated sludge regulated by CPAM and sawdust were investigated at a heating rate of 10~40 °C/min by using TGA method. The addition of sawdust enhanced the release of volatile substances and reduced the apparent activation energy of the sample. The maximum weight-loss rate decreased with the heating rate, and the DTG curves moved in the direction of high temperature. A model-free method, namely the Starink method, was adopted to calculate the apparent activation energies, which ranged from 135.3 kJ/mol to 174.8 kJ/mol. Combined with the master-plots method, the most appropriate mechanism function ultimately obtained was the nucleation-and-growth model.
Language	English
Publishing date	2023-05-21
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2527146-5
ISSN	2073-4360 ; 2073-4360
ISSN (online)	2073-4360
ISSN	2073-4360
DOI	10.3390/polym15102396
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Future climate change for major agricultural zones in China as projected by CORDEX-EA-II, CMIP5 and CMIP6 ensembles

Yu, Entao / Liu, Dongwei / Yang, Jianjun / Sun, Jianqi / Yu, Lingxue / King, Martin Peter

Atmospheric Research. 2023 June, v. 288 p.106731-

2023

Abstract: Understanding future climate change is crucial for securing and managing water supplies necessary for agricultural activities in China, particularly in rainfed agriculture regions. This paper evaluates the projected climate change for nine major ... ...

Abstract	Understanding future climate change is crucial for securing and managing water supplies necessary for agricultural activities in China, particularly in rainfed agriculture regions. This paper evaluates the projected climate change for nine major agricultural zones in China, using ensembles of regional climate models (RCMs) simulated under the Coordinated Regional Downscaling Experiment-East Asia second phase (CORDEX-EA-II) framework. The simulations were conducted for two climate scenarios (RCP2.6 and RCP8.5) at a 25 km grid spacing, with three RCMs (RegCM4, REMO, and WRF) driven by multiple CMIP5 global climate models (GCMs). The study compares the RCM simulations to the driving CMIP5 and the recent CMIP6 ensembles, focusing on surface temperature, precipitation, and surface relative humidity for the present day (1981–2010), mid-future (2036–2065), and far future (2070–2099) periods. The model evaluations indicate that the GCM and RCM simulations are consistent with observations, with RCMs showing better performance than the driving GCMs. The results show that both GCMs and RCMs project increased temperature and precipitation in most agricultural zones of China in the future, with the CMIP6 ensembles projecting the largest temperature increase and the CORDEX-EA-II ensemble showing the finest spatial details. Relative humidity is projected to decrease over major rice-producing areas of South China in the CORDEX-EA-II, CMIP5, and CMIP6 ensembles. This study provides valuable information to support climate change adaptation and mitigation efforts in China, particularly in the agricultural sectors.
Keywords	climate ; climate change ; rainfed farming ; relative humidity ; research ; surface temperature ; China ; CORDEX-EA-II ; Climate change projection ; Agricultural zones ; Model ensembles
Language	English
Dates of publication	2023-06
Publishing place	Elsevier B.V.
Document type	Article ; Online
ISSN	0169-8095
DOI	10.1016/j.atmosres.2023.106731
Database	NAL-Catalogue (AGRICOLA)

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Article: Footprints of Pacific Decadal Oscillation in the interdecadal variation of Consecutive Cloudy–Rainy Events in Southern China

Gu, Letian / Sun, Jianqi / Yu, Shui / Zhang, Mengqi

Atmospheric research. 2021 Aug. 10, v. 257

2021

Abstract: Consecutive Cloudy-Rainy Events (CCREs) in spring have a disastrous impact on agriculture and the natural ecosystem over southern China. In this study, the variability of the frequency of spring CCREs in southern China from 1961 to 2016 and the ... ...

Abstract	Consecutive Cloudy-Rainy Events (CCREs) in spring have a disastrous impact on agriculture and the natural ecosystem over southern China. In this study, the variability of the frequency of spring CCREs in southern China from 1961 to 2016 and the underlying mechanism of these phenomena are explored. The results indicate that the dominant mode of the CCRE frequency in southern China varies in a uniform spatial pattern, and the time series exhibits a strong interdecadal variation, with a higher frequency between the late 1970s and late 1990s and a lower frequency in the other periods. Such an interdecadal variation in the CCRE frequency varies well in–phase with the Pacific Decadal Oscillation (PDO). Further dynamic diagnosis and numerical simulation both suggest that the PDO is linked with CCREs in southern China through two physical processes. On the one hand, the anomalous PDO is associated with the anomalous North Pacific Oscillation (NPO). The westward extension of the NPO is accompanied by anomalous East Asian westerly jet (EAWJ) and West Pacific subtropical high (WPSH). On the other hand, the eastward development process associated with the PDO variation can excite a Rossby wave train over the Northern Hemispheric mid-latitudes. The PDO-related Rossby wave train can alter East Asian atmospheric circulations, leading to anomalous EAWJ. The changes in the EAWJ and WPSH can further lead to anomalous upward motion over southern China and moisture transportation from the South China Sea to southern China. Through these physical processes, the positive–phase (negative–phase) PDO provides a favorable (unfavorable) condition for the occurrence of CCREs in southern China.
Keywords	ecosystems ; latitude ; mathematical models ; research ; spring ; time series analysis ; transportation ; China ; South China Sea
Language	English
Dates of publication	2021-0810
Publishing place	Elsevier B.V.
Document type	Article
Note	NAL-AP-2-clean
ISSN	0169-8095
DOI	10.1016/j.atmosres.2021.105609
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: A CT reconstruction method based on constrained data fidelity range estimation.

Cao, Pengxin / Zhao, Jun / Sun, Jianqi

Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference

2021 Volume 2021, Page(s) 2782–2785

Abstract: For the CT iterative reconstruction, choosing the parameters of different regularization terms has been a difficult problem. Transforming the reconstruction problem into constrained optimization can solve this problem, but determining the constraint ... ...

Abstract	For the CT iterative reconstruction, choosing the parameters of different regularization terms has been a difficult problem. Transforming the reconstruction problem into constrained optimization can solve this problem, but determining the constraint range and accurately solving it remains a challenge. This paper proposes a CT reconstruction method based on constrained data fidelity term, which estimates the distribution of the constraint function by Taylor expansion to determine the constraint range. We respectively use Douglas-Rachford splitting (DRS) and Projection-based primal-dual algorithm (PPD) to split the reconstruction problem and solve the data fidelity subproblem. This method can accurately estimate the constrained range of data fidelity terms to ensure reconstruction accuracy and use different regularization terms for reconstruction without parameter adjustment. Three regularization terms are used for reconstruction experiments, and simulation results show that the proposed method can converge stably, and its reconstruction quality is better than the filtered back-projection.
MeSH term(s)	Algorithms ; Image Processing, Computer-Assisted ; Phantoms, Imaging ; Tomography, X-Ray Computed
Language	English
Publishing date	2021-12-07
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	2694-0604
ISSN (online)	2694-0604
DOI	10.1109/EMBC46164.2021.9631063
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Reduced vowel space in video conferences via Zoom: Evidence from read speecha).

Belz, Malte / Ebert, Melissa / Müller, Miriam / Sun, Jianqi / Terada, Megumi / Xia, Qiang

JASA express letters

2023 Volume 3, Issue 10

Abstract: This exploratory study compared vowel space area (VSA) in face-to-face situations and video conference situations using the software Zoom. Twenty native German participants read word lists recorded before and after spontaneous conversation. The overall ... ...

Abstract	This exploratory study compared vowel space area (VSA) in face-to-face situations and video conference situations using the software Zoom. Twenty native German participants read word lists recorded before and after spontaneous conversation. The overall VSA in Zoom was reduced significantly by 11.9%, with a more reduced VSA before and less reduction after the spontaneous conversation. Of nine peripheral vowels in German, /aː iː yː/ showed a significantly reduced Euclidean distance to the centroid of the vowel space. The observed hypoarticulation is discussed in light of the experimental setup, situational differences, and less involvement in Zoom than in face-to-face situations.
MeSH term(s)	Humans ; Speech Acoustics ; Phonetics ; Speech Intelligibility
Language	English
Publishing date	2023-10-16
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	2691-1191
ISSN (online)	2691-1191
DOI	10.1121/10.0021315
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Survival Analysis for Multimode Ablation Using Self-Adapted Deep Learning Network Based on Multisource Features.

Zhao, Ziqi / Li, Wentao / Liu, Ping / Zhang, Aili / Sun, Jianqi / Xu, Lisa X

IEEE journal of biomedical and health informatics

2023 Volume PP

Abstract: Novel multimode thermal therapy by freezing before radio-frequency heating has achieved a desirable therapeutic effect in liver cancer. Compared with surgical resection, ablation treatment has a relatively high risk of tumor recurrence. To monitor tumor ... ...

Abstract	Novel multimode thermal therapy by freezing before radio-frequency heating has achieved a desirable therapeutic effect in liver cancer. Compared with surgical resection, ablation treatment has a relatively high risk of tumor recurrence. To monitor tumor progression after ablation, we developed a novel survival analysis framework for survival prediction and efficacy assessment. We extracted preoperative and postoperative MRI radiomics features and vision transformer-based deep learning features. We also combined the immune features extracted from peripheral blood immune responses using flow cytometry and routine blood tests before and after treatment. We selected features using random survival forest and improved the deep Cox mixture (DCM) for survival analysis. To properly accommodate multitype input features, we proposed a self-adapted fully connected layer for locally and globally representing features. We evaluated the method using our clinical dataset. Of note, the immune features rank the highest feature importance and contribute significantly to the prediction accuracy. The results showed a promising C
Language	English
Publishing date	2023-03-31
Publishing country	United States
Document type	Journal Article
ZDB-ID	2695320-1
ISSN	2168-2208 ; 2168-2194
ISSN (online)	2168-2208
ISSN	2168-2194
DOI	10.1109/JBHI.2023.3260776
Database	MEDical Literature Analysis and Retrieval System OnLINE

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