气候变化领域集成服务门户(CCPortal): Phase inconsistency as a major source of error in NGFS forecast

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DOI	10.1007/s00382-020-05148-y
	Phase inconsistency as a major source of error in NGFS forecast
	Singhai P.; Balakrishnan S.; Rajagopal E.N.; Chakraborty A.
发表日期	2020
ISSN	0930-7575
起始页码	2797
结束页码	2814
卷号	54
英文摘要	South Asian monsoon exhibits multiscale spatiotemporal variability. Analyzing the nature and behavior of numerical weather forecast error associated with these space-time heterogeneities will eventually help in improving the models. We investigate the spatiotemporal error characteristics of the National Centre for Medium-Range Weather Forecasting (NCMRWF) Global Forecast System (NGFS) model over South Asian land and ocean separately. Although error grows with lead-time, it saturates within 3–5 days of forecast initiation. The saturated error is only about 15–25% higher than that of day-1, indicating that most of the error accumulates within first 24-h of forecast. Increase in error over oceanic regions is due to an increase in the area with high error at all precipitation ranges with large day-to-day variability. However, over land error growth is primarily confined at locations of high mean precipitation. Decomposition of error arising due to intensity and phase variations reveals that about 90% of it arises from the model’s inability to capture phase of precipitation at various timescales. We show that NGFS cannot capture synoptic scale variations (< 10 day) after day-2. Both the high-frequency (10–20 day) and low-frequency (30–60 day) intraseasonal variations are reasonably predicted up to day-3. At diurnal timescale, NGFS forecasts show a peak in precipitation about 3–6 h prior to that observed, both over land and ocean. Surprisingly, this error does not change with lead-time. Lastly, we show that major error characteristics do not depend on the seasonal mean monsoon rainfall. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Diurnal cycle; Indian monsoon; Phase error; Short-to-medium range forecast
语种	英语
scopus关键词	decomposition analysis; error analysis; land-sea interaction; monsoon; precipitation assessment; spatiotemporal analysis; weather forecasting; South Asia
来源期刊	Climate Dynamics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/145561
作者单位	Centre for Atmospheric and Oceanic Sciences, and Divecha Centre for Climate Change, Indian Institute of Science, Bengaluru, Karnataka 560012, India; India Meteorological Department, New Delhi, 110037, India; National Centre for Medium Range Weather Forecasting, Noida, Uttar Pradesh 201309, India
推荐引用方式 GB/T 7714	Singhai P.,Balakrishnan S.,Rajagopal E.N.,et al. Phase inconsistency as a major source of error in NGFS forecast[J],2020,54.
APA	Singhai P.,Balakrishnan S.,Rajagopal E.N.,&Chakraborty A..(2020).Phase inconsistency as a major source of error in NGFS forecast.Climate Dynamics,54.
MLA	Singhai P.,et al."Phase inconsistency as a major source of error in NGFS forecast".Climate Dynamics 54(2020).