The relationship between the late spring North Atlantic Oscillation (NAO) and the summer extreme precipitation frequency (EPF) in the middle and lower reaches of the Yangtze River Valley (MLYRV) is examined using an N...The relationship between the late spring North Atlantic Oscillation (NAO) and the summer extreme precipitation frequency (EPF) in the middle and lower reaches of the Yangtze River Valley (MLYRV) is examined using an NECP/NCAR reanalysis dataset and daily precipitation data from 74 stations in the MLYRV. The results show a significant negative correlation between the May NAO index and the EPF over the MLYRV in the subsequent summer. In positive EPF index years, the East Asian westerly jet shifts farther southward, and two blocking high positive anomalies appear over the Sea of Okhotsk and the Ural Mountains. These anomalies are favorable to the cold air from the mid-high latitudes invading the Yangtze River Valley (YRV). The moisture convergence and the ascending motion dominate the MLYRV. The above patterns are reversed in negative EPF index years. A wave train pattern that originates from the North Atlantic extends eastward to the Mediterranean and then moves to the Tibetan Plateau and from there to the YRV, which is an important link in the May NAO and the summer extreme precipitation in the MLYRV. The wave train may be aroused by the tripole pattern of the SST, which can explain why the May NAO affects the summer EPF in the MLYRV.展开更多
An epidemiological survey of anisakid nematodes was conducted on 205 specimens of horse mackerel （Trachurus trachurus） and 183 of axillary seabream （Pagellus acarne） captured in the zone between Tangier and Larach...An epidemiological survey of anisakid nematodes was conducted on 205 specimens of horse mackerel （Trachurus trachurus） and 183 of axillary seabream （Pagellus acarne） captured in the zone between Tangier and Larache in the north Atlantic Moroccan＇s coasts. Three species of nematodes were morphologically identified： Anisakis simplex s.l., Hysterothylacium sp., Pseudotarranova sp. According to the season, the nematode most observed in T. trachurus was .4. simplex s.1. （the highest values of prevalence （100%）, the mean intensity （48.6）. Hysterothylacium sp. was the most frequent anisakid in P. acarne with 100% of prevalence and 34.46 of the mean intensity. The infestation parameters were also analyzed according to the host species length, noting a maximum of infected fish by Anisakis simplex s.1. （96%） in samples of horse mackerel larger than 28 cm, while in axiliary seabream, the highest prevalence of infestation by Hysterothylacium sp. （100%） was found in fish more than 29 cm.展开更多
基金supported by the National Basic Research Program of China(Grant No.2009CB421406)the special Fund for Public Welfare Industry(Meteorology)(Grant No.GYHY200906018)+1 种基金the National Nature Science Foundation of China(Grant No.41175071)the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.KZCX2-YW-QN202)
文摘The relationship between the late spring North Atlantic Oscillation (NAO) and the summer extreme precipitation frequency (EPF) in the middle and lower reaches of the Yangtze River Valley (MLYRV) is examined using an NECP/NCAR reanalysis dataset and daily precipitation data from 74 stations in the MLYRV. The results show a significant negative correlation between the May NAO index and the EPF over the MLYRV in the subsequent summer. In positive EPF index years, the East Asian westerly jet shifts farther southward, and two blocking high positive anomalies appear over the Sea of Okhotsk and the Ural Mountains. These anomalies are favorable to the cold air from the mid-high latitudes invading the Yangtze River Valley (YRV). The moisture convergence and the ascending motion dominate the MLYRV. The above patterns are reversed in negative EPF index years. A wave train pattern that originates from the North Atlantic extends eastward to the Mediterranean and then moves to the Tibetan Plateau and from there to the YRV, which is an important link in the May NAO and the summer extreme precipitation in the MLYRV. The wave train may be aroused by the tripole pattern of the SST, which can explain why the May NAO affects the summer EPF in the MLYRV.
文摘An epidemiological survey of anisakid nematodes was conducted on 205 specimens of horse mackerel （Trachurus trachurus） and 183 of axillary seabream （Pagellus acarne） captured in the zone between Tangier and Larache in the north Atlantic Moroccan＇s coasts. Three species of nematodes were morphologically identified： Anisakis simplex s.l., Hysterothylacium sp., Pseudotarranova sp. According to the season, the nematode most observed in T. trachurus was .4. simplex s.1. （the highest values of prevalence （100%）, the mean intensity （48.6）. Hysterothylacium sp. was the most frequent anisakid in P. acarne with 100% of prevalence and 34.46 of the mean intensity. The infestation parameters were also analyzed according to the host species length, noting a maximum of infected fish by Anisakis simplex s.1. （96%） in samples of horse mackerel larger than 28 cm, while in axiliary seabream, the highest prevalence of infestation by Hysterothylacium sp. （100%） was found in fish more than 29 cm.
