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Biến động của các sự kiện thời tiết cực đoan ở Đông Phi xích đạo, một nghiên cứu trường hợp về lượng mưa tại Kenya và Uganda
Tóm tắt
Nghiên cứu này điều tra sự biến thiên của các sự kiện mưa cực đoan ở Đông Phi (EA), sử dụng các chỉ số từ Nhóm Chuyên gia về Phát hiện Biến đổi Khí hậu và các chỉ số của Tổ chức Khí tượng Thế giới (WMO) (ETCCDI). Phân tích dựa trên dữ liệu quan sát lượng mưa hàng ngày của 23 trạm khí tượng, với độ dài thay đổi từ 1961 đến 2010. Các chỉ số được xem xét bao gồm: số ngày mưa (R ≥1 mm), tổng lượng mưa hàng năm trong các ngày mưa (PRCPTOT), chỉ số cường độ hàng ngày đơn giản (SDII), số ngày mưa lớn (R ≥ 10 mm), số ngày mưa rất lớn (R ≥ 20 mm), và mưa nghiêm trọng (R ≥ 50 mm). Phân tích thống kê Mann-Kendall không tham số đã được thực hiện để xác định xu hướng trong dữ liệu. Phân bố lượng mưa theo thời gian khác nhau giữa các trạm. Hầu hết tất cả các chỉ số được xem xét đều giảm theo thời gian. Phân tích cho thấy PRCPTOT, lượng mưa rất lớn, và lượng mưa nghiêm trọng nói chung đang giảm một cách không đáng kể ở mức ý nghĩa 5%. PRCPTOT rõ ràng đang giảm ở các khu vực Đất khô và Bán khô (ASAL) so với các khu vực khác của EA. Số ngày ghi nhận mưa lớn nhìn chung đang giảm nhưng bắt đầu tăng lên trong thập kỷ qua mặc dù các thay đổi là không đáng kể. Cả PRCPTOT và lượng mưa lớn đều cho thấy một sự phục hồi trong xu hướng bắt đầu từ những năm 1990. SDII cho thấy sự giảm ở hầu hết các khu vực, đặc biệt là ở ASAL. Những thay đổi này có thể chỉ ra sự biến đổi và thay đổi khí hậu đang diễn ra, điều chỉnh chế độ lượng mưa của EA. Kết quả này là cơ sở cho nghiên cứu tiếp theo, sử dụng các bộ dữ liệu dài hơn trên toàn bộ khu vực để giảm thiểu các sự tổng quát đưa ra ở đây. Việc giám sát liên tục các sự kiện cực đoan ở EA là rất quan trọng, với dự đoán lượng mưa sẽ tăng lên trong thế kỷ hai mươi mốt.
Từ khóa
#đông phi #thời tiết cực đoan #lượng mưa #biến đổi khí hậu #khí tượng họcTài liệu tham khảo
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