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  • 1
    Online Resource
    Online Resource
    A Study on the Reduction of Forecast Error Variance by Three Adaptive Observation Approaches for Tropical Cyclone Prediction
    American Meteorological Society ; 2011
    In:  Monthly Weather Review Vol. 139, No. 7 ( 2011-07-01), p. 2218-2232
    Details
    In: Monthly Weather Review, American Meteorological Society, Vol. 139, No. 7 ( 2011-07-01), p. 2218-2232
    Abstract: Three adaptive approaches for tropical cyclone prediction are compared in this study: the conditional nonlinear optimal perturbation (CNOP) method, the first singular vector (FSV) method, and the ensemble transform Kalman filter (ETKF) method. These approaches are compared for 36-h forecasts of three northwest Pacific tropical cyclones (TCs): Matsa (2005), Nock-Ten (2004), and Morakot (2009). The sensitive regions identified by each method are obtained. The CNOPs form an annulus around the storm at the targeting time, the FSV targets areas north of the storm, and the ETKF closely targets the typhoon location itself. The sensitive results of both the CNOPs and FSV collocate well with the steering flow between the subtropical high and the TCs. Furthermore, the regions where the convection is strong are targeted by the CNOPs. Relatively speaking, the ETKF sensitive results reflect the large-scale flow. To identify the most effective adaptive observational network, numerous probes or flights were tested arbitrarily for the ETKF method or according to the calculated sensitive regions of the CNOP and FSV methods. The results show that the sensitive regions identified by these three methods are more effective for adaptive observations than the other regions. In all three cases, the optimal adaptive observational network identified by the CNOP and ETKF methods results in similar forecast improvements in the verification region at the verification time, while the improvement using the FSV method is minor.
    Type of Medium: Online Resource
    ISSN: 0027-0644 , 1520-0493
    URL: Article
    DOI: 10.1175/2010MWR3327.1
    RVK:
    RA 1000
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2011
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    detail.hit.zdb_id: 202616-8
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  • 2
    Online Resource
    Online Resource
    Zigzag Oscillations in Variational Data Assimilation with Physical “On–Off” Processes
    American Meteorological Society ; 2005
    In:  Monthly Weather Review Vol. 133, No. 9 ( 2005-09-01), p. 2711-2720
    Details
    In: Monthly Weather Review, American Meteorological Society, Vol. 133, No. 9 ( 2005-09-01), p. 2711-2720
    Abstract: Using an idealized model of a partial differential equation with parameterization “on–off” switches in the forcing term, the impacts of on–off switches on the variational data assimilation (VDA) are investigated in this paper. It is shown that the traditional time discretization at the switches of the discrete forward model could induce awful zigzags in the associated discrete cost function (CF), which would cause the optimization to fail to work well in the VDA when using the adjoint method. In addition, it can also cause zigzag oscillations in the numerical solution of the model. A method, which is a generalization of Xu’s intermediate interpolation method, is proposed to eliminate the zigzag phenomenon. The potential merits of this treatment are examined by numerical experiments. The results show that through this treatment, the convergence in the minimization processes of the VDA is improved and the satisfactory optimization retrievals are obtained even though the adjoint models are constructed following Zou’s method from the discrete forward model with the traditional time discretization at the switches.
    Type of Medium: Online Resource
    ISSN: 1520-0493 , 0027-0644
    URL: Article
    DOI: 10.1175/MWR2995.1
    RVK:
    RA 1000
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2005
    detail.hit.zdb_id: 2033056-X
    detail.hit.zdb_id: 202616-8
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  • 3
    Online Resource
    Online Resource
    The Impact of Assimilating Dropwindsonde Data Deployed at Different Sites on Typhoon Track Forecasts
    American Meteorological Society ; 2013
    In:  Monthly Weather Review Vol. 141, No. 8 ( 2013-08-01), p. 2669-2682
    Details
    In: Monthly Weather Review, American Meteorological Society, Vol. 141, No. 8 ( 2013-08-01), p. 2669-2682
    Abstract: This study investigates the impacts on typhoon track forecasting by the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5) and its three-dimensional variational data assimilation (3DVAR) system of assimilating dropwindsonde observational data acquired from different sites. All of the sonde data were obtained between 2004 and 2009 in the typhoon surveillance program Dropwindsonde Observations for Typhoon Surveillance near the Taiwan Region (DOTSTAR). Experiments were conducted to test the model's response to five scenarios involving differing dropwindsonde data inputs: 1) no dropwindsonde data, 2) all available dropwindsonde data, 3) data gathered in sensitive regions identified by the conditional nonlinear optimal perturbation (CNOP) approach, 4) data gathered in sensitive regions identified by the first singular vector (FSV) approach, and 5) several sondes selected at random. The results show that using dropwindsonde data based on CNOP sensitivity can lead to improvements in typhoon track forecasting similar to, and occasionally better than, those achieved by assimilating all of the available data. Both approaches offered greater benefits than the other three alternatives averagely. It is proposed that CNOP provides a suitable approach to determining sensitive regions during adaptive observation of typhoons. Similar results may be obtained if the sensitivity products developed using MM5 are employed in the Weather Research and Forecasting Model (WRF), suggesting that it is applicable to utilize sensitivity produced by MM5 in WRF.
    Type of Medium: Online Resource
    ISSN: 0027-0644 , 1520-0493
    URL: Article
    DOI: 10.1175/MWR-D-12-00142.1
    RVK:
    RA 1000
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2013
    detail.hit.zdb_id: 2033056-X
    detail.hit.zdb_id: 202616-8
    SSG: 14
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  • 4
    Online Resource
    Online Resource
    Initial condition and parameter estimation in physical 'on-off' processes by variational data assimilation
    Stockholm University Press ; 2005
    In:  Tellus A Vol. 57, No. 5 ( 2005-10), p. 736-741
    Details
    In: Tellus A, Stockholm University Press, Vol. 57, No. 5 ( 2005-10), p. 736-741
    Type of Medium: Online Resource
    ISSN: 0280-6495 , 1600-0870
    URL: Issue
    URL: Article
    DOI: 10.1111/tea.2005.57.issue-5
    DOI: 10.1111/j.1600-0870.2005.00137.x
    RVK:
    RA 1000
    RVK:
    UA 8382.1
    Language: English
    Publisher: Stockholm University Press
    Publication Date: 2005
    detail.hit.zdb_id: 2026987-0
    SSG: 16,13
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  • 5
    Online Resource
    Online Resource
    Developing a reversible rapid coordinate transformation model for the cylindrical projection
    Elsevier BV ; 2016
    In:  Computers & Geosciences Vol. 89 ( 2016-04), p. 44-56
    Details
    In: Computers & Geosciences, Elsevier BV, Vol. 89 ( 2016-04), p. 44-56
    Type of Medium: Online Resource
    ISSN: 0098-3004
    URL: Article
    DOI: 10.1016/j.cageo.2016.01.007
    RVK:
    RA 1000
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2016
    detail.hit.zdb_id: 1499977-8
    SSG: 16,13
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  • 6
    Online Resource
    Online Resource
    Hydrological change and human activity during Yuan–Ming Dynasties in the Loulan area, northwestern China
    SAGE Publications ; 2018
    In:  The Holocene Vol. 28, No. 8 ( 2018-08), p. 1266-1275
    Details
    In: The Holocene, SAGE Publications, Vol. 28, No. 8 ( 2018-08), p. 1266-1275
    Abstract: Human activity on arid lands has been related to oases evolution. The ancient Loulan, an important transportation hub of the ancient Silk Road, developed on an ancient oasis on the west bank of the lake Lop Nur in Xinjiang, China. Previous studies and historical documents suggest that the region has experienced dramatic natural environmental and human activity–related changes over time, transitioning from a particularly prosperous oasis to a depopulated zone with harsh environment after about 1500 a BP (before present, where present = AD 1950). Based on systematic radiocarbon ( 14 C) dating for natural plant remains and archeological sites in the Loulan area, it was revealed that the region re-experienced oasis environment from 1260 to 1450 cal. AD, corresponding to the Yuan–Ming Dynasties, which is the climate transition stage from the ‘Medieval Warm Period’ to the ‘Little Ice Age’, encompassing a series of pulse-like flood events which cannot be identified from lacustrine deposition due to the limits of sampling resolution and dating. It was found that humans re-occupied the Loulan area and built canals to irrigate farmlands during the period. The more habitable hydrological conditions that resulted from these environmental changes present one major reason for the re-emergence of human activities in the Loulan area.
    Type of Medium: Online Resource
    ISSN: 0959-6836 , 1477-0911
    URL: Article
    DOI: 10.1177/0959683618771495
    RVK:
    RA 1000
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2018
    detail.hit.zdb_id: 2027956-5
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    SSG: 3,4
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  • 7
    Online Resource
    Online Resource
    Hydro-climatic aspects of prehistoric human dynamics in the drylands of the Asian interior
    SAGE Publications ; 2023
    In:  The Holocene Vol. 33, No. 2 ( 2023-02), p. 194-207
    Details
    In: The Holocene, SAGE Publications, Vol. 33, No. 2 ( 2023-02), p. 194-207
    Abstract: The causes of prehistoric human migrations in the drylands of the Asian interior have long been debated among multidisciplinary scholars. The Bronze Age Xiaohe settlements (ca. 4000–3300 cal yr BP) are situated in the extremely arid Tarim Basin of northwest China and exemplify a societal collapse which included a long-distance movement along river catchments. Here, we present the results of stable carbon isotope values (δ 13 C) of archaeobotanical remains, sedimentary faces analysis from the Tarim River catchment, and a compilation of palaeo-environmental evidence in order to investigate potential relationships between regional environmental changes and the response of prehistoric societies in this arid region. Results suggest that the early Xiaohe population was forced to migrate as a consequence of the deterioration of hydrological conditions around settlements. The decline of Xiaohe Culture occurred in the context of decreasing water availability in the basin interior due to climatic change lasting several hundred years. Results are potentially significant for the management of ecologically fragile dryland habitats, particularly the watershed terminus area, threatened by ongoing climate change, specifically in the context of the need to manage scarce water resources to promote sustainable socioeconomic development.
    Type of Medium: Online Resource
    ISSN: 0959-6836 , 1477-0911
    URL: Article
    DOI: 10.1177/09596836221131694
    RVK:
    RA 1000
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2023
    detail.hit.zdb_id: 2027956-5
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    SSG: 3,4
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  • 8
    Online Resource
    Online Resource
    Link between black carbon, fires, climate change, and human activity during the Holocene period shown in the loess-paleosol sequence from Henan, China
    Cambridge University Press (CUP) ; 2017
    In:  Quaternary Research Vol. 87, No. 2 ( 2017-03), p. 288-297
    Details
    In: Quaternary Research, Cambridge University Press (CUP), Vol. 87, No. 2 ( 2017-03), p. 288-297
    Abstract: Henan was the site of development for several ancient cultures during the Holocene. In this study, black carbon (BC) in the Holocene sediment is compared with known climatic changes and cultural events to provide information concerning the link between fire, climatic changes, and human activity in Xiangcheng. Prior to 8000 cal yr BP, the occurrence of fires was low under cold and dry climatic conditions. The BC content in 8000–1000calyrBP indicates a gradual increase in fire, with two peak values at 7500calyrBP and 3500 cal yr BP. The first peak correlates to the development of the Peiligang culture, and the second peak correlates to the development of wet and warm climate conditions along with the appearance of the Xia–Shang dynasties. Increases in fire activity could therefore be attributed to climate change and the development of human civilization in the region. Another sharp increase in fires around 1000calyrBP was consistent with a sharp increase in population during the Tang dynasty.
    Type of Medium: Online Resource
    ISSN: 0033-5894 , 1096-0287
    URL: Article
    DOI: 10.1017/qua.2016.18
    RVK:
    RA 1000
    Language: English
    Publisher: Cambridge University Press (CUP)
    Publication Date: 2017
    detail.hit.zdb_id: 1471589-2
    detail.hit.zdb_id: 205711-6
    SSG: 13
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  • 9
    Online Resource
    Online Resource
    Oasis landscape of the ancient Loulan on the west bank of Lake Lop Nur, Northwest China, inferred from vegetation utilization for architecture
    SAGE Publications ; 2019
    In:  The Holocene Vol. 29, No. 6 ( 2019-06), p. 1030-1044
    Details
    In: The Holocene, SAGE Publications, Vol. 29, No. 6 ( 2019-06), p. 1030-1044
    Abstract: The ancient Loulan, situated on the west bank of Lake Lop Nur, Xinjiang, Northwest China, was an important town on the Silk Road connecting China to Europe. However, this once-prosperous kingdom has been a depopulated zone filled with wind-eroded mounds since approximately AD 500–600. A comprehensive understanding of the environmental setting of the flourishing Loulan civilization is a prerequisite for assessing environment–human interaction there. Here, we present our survey, chronology, and archaeobotany (the identification of plant remains) of vegetation use for architecture from eight ancient ruins of the Loulan kingdom to clarify the ecological landscape on the west bank of Lake Lop Nur and to assess paleoenvironmental conditions when the Loulan kingdom flourished. Our results suggest that Populus euphratica, tamarisk ( Tamarix Linn), and reed ( Phragmites Trin.) were most widely used as building materials in this period. Wood utilization for buildings depended entirely on indigenous vegetation rather than that of the mountains in the Loulan kingdom, even though the Loulan was a predominant transportation hub on the prosperous Silk Road. Our reconstruction indicates that the west bank of Lake Lop Nur was sufficiently wetter than present conditions to support riparian forest growth composed mainly of P. euphratica, tamarisk shrubs, and reed meadows, until approximately AD 500. These wetter conditions and flourishing civilization accompanied an increase in precipitation in arid central Asia. Conversely, combined evidence of both archeological and paleoclimatic records from the water sources of Lake Lop Nur and ancient oases suggest that abrupt decreased mountain precipitation could be considered a significant environmental factor in the decline of Loulan kingdom.
    Type of Medium: Online Resource
    ISSN: 0959-6836 , 1477-0911
    URL: Article
    DOI: 10.1177/0959683619831423
    RVK:
    RA 1000
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2019
    detail.hit.zdb_id: 2027956-5
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  • 10
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    Sea level anomaly intelligent inversion model based on LSTM-RBF network
    Springer Science and Business Media LLC ; 2021
    In:  Meteorology and Atmospheric Physics Vol. 133, No. 2 ( 2021-04), p. 245-259
    Details
    In: Meteorology and Atmospheric Physics, Springer Science and Business Media LLC, Vol. 133, No. 2 ( 2021-04), p. 245-259
    Type of Medium: Online Resource
    ISSN: 0177-7971 , 1436-5065
    URL: Article
    DOI: 10.1007/s00703-020-00745-2
    RVK:
    RA 1000
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2021
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    detail.hit.zdb_id: 863-1
    detail.hit.zdb_id: 1462145-9
    SSG: 16,13
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