scholarly journals A statistical model linking Siberian forest fire scars with early summer rainfall anomalies

2006 ◽  
Vol 33 (14) ◽  
Author(s):  
Tim E. Jupp ◽  
Christopher M. Taylor ◽  
Heiko Balzter ◽  
Charles T. George
Keyword(s):  
Statistical Model ◽  
Forest Fire ◽  
Summer Rainfall ◽  
Early Summer ◽  
Fire Scars ◽  
Rainfall Anomalies

Distinct Principal Modes of Early and Late Summer Rainfall Anomalies in East Asia*

2009 ◽  
Vol 22 (13) ◽  
pp. 3864-3875 ◽  
Author(s):  
Bin Wang ◽  
Jian Liu ◽  
Jing Yang ◽  
Tianjun Zhou ◽  
Zhiwei Wu
Keyword(s):  
East Asia ◽  
Summer Monsoon ◽  
Land Surface ◽  
Southern Oscillation ◽  
Southern China ◽  
Late Summer ◽  
Summer Rainfall ◽  
Seasonal Prediction ◽  
Early Summer ◽  
Rainfall Anomalies

Abstract The current seasonal prediction of East Asia (EA) summer monsoon deals with June–July–August (JJA) mean anomalies. This study shows that the EA summer monsoon may be divided into early summer [May–June (MJ)] and late summer [July–August (JA)] and exhibits remarkable differences in mean state between MJ and JA. This study reveals that the principal modes of interannual precipitation variability have distinct spatial and temporal structures during the early and late summer. These principal modes can be categorized as either El Niño–Southern Oscillation (ENSO) related or non-ENSO related. During the period of 1979–2007, ENSO-related modes explain 35% of MJ variance and 45% of JA variance, and non-ENSO-related modes account for 25% of MJ variance and 20% of JA variance. For ENSO-related variance, about two-thirds are associated with ENSO decaying phases, and one-third is associated with ENSO developing phases. The ENSO-related MJ modes generally concur with rapid decay or early development of ENSO episodes, and the opposite tends to apply to ENSO-related JA modes. The non-ENSO MJ mode is preceded by anomalous land surface temperatures over southern China during the previous March and April. The non-ENSO JA mode is preceded by lasting equatorial western Pacific (the Niño-4 region) warming from the previous winter through late summer. The results suggest that 1) prediction of bimonthly (MJ) and (JA) anomalies may be useful, 2) accurate prediction of the detailed evolution of ENSO is critical for prediction of ENSO-related bimonthly rainfall anomalies over East Asia, and 3) non-ENSO-related modes are of paramount importance during ENSO neutral years. Further establishment of the physical linkages between the non-ENSO modes and their corresponding precursors may provide additional sources for EA summer monsoon prediction.

Subseasonal Variation in ENSO-Related East Asian Rainfall Anomalies during Summer and Its Role in Weakening the Relationship between the ENSO and Summer Rainfall in Eastern China since the Late 1970s

2011 ◽  
Vol 24 (9) ◽  
pp. 2271-2284 ◽  
Author(s):  
Hong Ye ◽  
Riyu Lu
Keyword(s):  
Eastern China ◽  
Late Summer ◽  
Summer Rainfall ◽  
Rainfall Anomaly ◽  
Precipitation Anomaly ◽  
Early Summer ◽  
Huai River ◽  
Rainfall Anomalies ◽  
Circulation Anomalies ◽  
The Relationship

Abstract The findings of the study reported in this paper show that, during ENSO decaying summers, rainfall and circulation anomalies exhibit clear subseasonal variation. Corresponding to a positive (negative) December–February (DJF) Niño-3.4 index, a positive (negative) subtropical rainfall anomaly, with a southwest–northeast tilt, appears in South China and the western North Pacific (WNP) in the subsequent early summer (from June to middle July) but advances northward into the Huai River Basin in China as well as Korea and central Japan in late summer (from late July to August). Concurrently, a lower-tropospheric anticyclonic anomaly over the WNP extends northward from early to late summer. The seasonal change in the basic flows, characterized by the northward shift of the upper-tropospheric westerly jet and the WNP subtropical high, is suggested to be responsible for the differences in the above rainfall and circulation anomalies between early and late summer by inducing distinct extratropical responses even under the almost identical tropical forcing of a precipitation anomaly in the Philippine Sea. A particular focus of the study is to investigate, using station rainfall data, the subseasonal variations in ENSO-related rainfall anomalies in eastern China since the 1950s, to attempt to examine their role in weakening the relationship between the ENSO and summer mean rainfall in eastern China since the late 1970s. It is found that the ENSO-related rainfall anomalies tend to be similar between early and late summer before the late 1970s, that is, the period characterized by a stronger ENSO–summer mean rainfall relationship. After the late 1970s, however, the anomalous rainfall pattern in eastern China is almost reversed between early and late summer, resulting accordingly in a weakened relationship between the ENSO and total summer rainfall in eastern China.

The influence of supplementary feeding on growth and fertility of beef heifers grazing natural pastures

1968 ◽  
Vol 8 (33) ◽  
pp. 425 ◽  
Author(s):  
EJ Sparke ◽  
DR Lamond
Keyword(s):  
New South ◽  
Age Groups ◽  
Summer Rainfall ◽  
Early Summer ◽  
Protein Supplementation ◽  
Low Fertility ◽  
Winter Period ◽  
Target Weight ◽  
South Wales ◽  
North Eastern

This paper reports an experiment examining the effect of age and protein supplementation on growth and fertility of Shorthorn-Devon cross heifers grazing natural pastures in the summer rainfall, subtropical environment of the Upper Clarence valley, north-eastern New South Wales. Heifers born over the period October to January 1963-64 were weaned in June 1964 and allotted at random within age groups (by month of birth) to a supplemented or non-supplemented treatment. The supplemented heifers were given linseed meal during the dry winter period each year from 1964 to 1966 inclusive (May-June to September-October). They were weighed each month and joined with bulls in the early summer of 1965 (2 years) and 1966 (3 years). They were examined for pregnancy in the autumn, and their calves were identified at birth. Supplemented heifers gained weight throughout and non-supplemented heifers generally lost weight in the winter periods. At two years fertility was closely related to liveweight at joining in supplemented heifers, but not in others. Heifers born in January gave the poorest reproductive performance, as the two supplemented ones that became pregnant in 1965 died at calving, and two-thirds of the non-supplemented ones were still empty after joining as 3-year-olds. The advantage of high 2-year-old fertility gained by heifers born in October and November, due to their greater size at joining, was partly offset by low fertility when lactating the following year. It is concluded that a decision as to whether a heifer should be supplemented during a period of nutritional stress prior to joining ought to be based on the probability of her reaching a prescribed target weight at joining as a result of receiving the supplement. The target weight for lactating heifers was at least 100 Ib higher than for dry hdfers. The results also indicate specific areas for further research.

scholarly journals Oceanic Forcings of the Interdecadal Variability in East Asian Summer Rainfall

2016 ◽  
Vol 29 (21) ◽  
pp. 7633-7649 ◽  
Author(s):  
Dong Si ◽  
Yihui Ding
Keyword(s):  
Yangtze River ◽  
Summer Rainfall ◽  
Yangtze River Valley ◽  
River Valley ◽  
Interdecadal Variability ◽  
Huaihe River ◽  
Huaihe River Valley ◽  
Leading Mode ◽  
Rainfall Anomalies ◽  
The 1960S

Abstract In this study, it was found that the Pacific decadal oscillation (PDO) and the Atlantic multidecadal oscillation (AMO) are shown to be the two major drivers of the interdecadal variability of summer rainfall over East Asia. The first leading mode (PC1) of this interdecadal variability—associated with an in-phase variation of rainfall anomalies along the Yangtze River valley and Huanghe–Huaihe River valley in China—is attributed to the PDO, while the second leading mode (PC2)—associated with seesawlike rainfall anomalies between the Yangtze River valley and Huanghe–Huaihe River valley—is attributed to the AMO. The AMO teleconnects its influence to the East Asian region, and beyond, through a circumglobal stationary baroclinic wave train extending from the Atlantic Ocean, through the Eurasian continent, and extending to North America. The AMO also altered the nature of the PDO through this atmospheric teleconnection, resulting in the occurrence of a different PDO pattern (“pseudo-PDO”) between the 1960s and 2010s. The pseudo-PDO has a different anomalous SST pattern in both the tropical and midlatitude Pacific compared to the conventional PDO. The pseudo-PDO causes a distinct atmospheric response in East Asia leading to an opposite relationship with the PC1 compared to the conventional PDO, thus leading to a change in the direction of the influence of the PDO on PC1 between the 1880s–1950s and the 1960s–2010s.

scholarly journals Modulation of PDO on the predictability of the interannual variability of early summer rainfall over south China

2013 ◽  
Vol 118 (23) ◽  
pp. 13,008-13,021 ◽  
Author(s):  
Wansuo Duan ◽  
Linye Song ◽  
Yun Li ◽  
Jiangyu Mao
Keyword(s):  
Interannual Variability ◽  
South China ◽  
Summer Rainfall ◽  
Early Summer

Effect of the East Asian Westerly Jet’s Intensity on Summer Rainfall in the Yangtze River Valley and Its Mechanism

2016 ◽  
Vol 29 (7) ◽  
pp. 2395-2406 ◽  
Author(s):  
Shixin Wang ◽  
Hongchao Zuo
Keyword(s):  
Yangtze River ◽  
Interannual Variation ◽  
East Asian ◽  
Summer Rainfall ◽  
Early Summer ◽  
Yangtze River Valley ◽  
River Valley ◽  
The Yellow Sea ◽  
The Yangtze River ◽  
Warm Advection

Abstract Many studies have shown that the northward (southward) displacement of the East Asian westerly jet (EAWJ) drastically reduces (increases) summer rainfall in the Yangtze River valley (YRV). However, the effect of the jet’s intensity on interannual variation in summer rainfall has not been systematically studied. The present study investigates the effect of the EAWJ’s intensity on this interannual variation and analyzes the mechanism by which this process occurs. In early summer, the EAWJ consists of two branches: one located over northern continental East Asia [western branch (EAWJWB)] and one extending from southern China to the northern Pacific [eastern branch (EAWJEB)]. The former merges into the latter over the Yellow Sea. A stronger EAWJEB leads to increased rainfall in the YRV, while the EAWJWB does not significantly affect rainfall in the YRV. The faster EAWJEB directly strengthens midtropospheric warm advection over the YRV because the corresponding changes in the meridional wind and horizontal temperature gradient are insignificant. The strengthened warm advection increases rainfall in the YRV by accelerating both adiabatic ascent and the ascent associated with diabatic heating primarily generated by convection. In midsummer, the EAWJ has no branches and is located over the midlatitudes of Asia. The strengthening of the EAWJ reduces rainfall in the YRV in midsummer through the Pacific–Japan (PJ) pattern. As the EAWJ strengthens, the PJ pattern turns to its positive phase. This results in the deceleration of the midtropospheric westerly wind and a reduction in the meridional temperature contrast, which weakens midtropospheric warm advection. The weakened warm advection in turn reduces rainfall in the YRV, following the process outlined for early summer.

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