{'fraction_non_alphanumeric': 0.020462633451957295, 'fraction_numerical': 0.014234875444839857, 'mean_word_length': 5.181318681318682, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Temporal and Spatial Evolution of the Asian Summer Monsoon in the Seasonal Cycle of Synoptic Fields

Abstract The principal mode of the seasonal variation of the Asian summer monsoon (ASM) and the temporal and spatial evolution of the corresponding synoptic fields are investigated via cyclostationary EOF analysis. This study uses the 21-yr (1979–99) Xie–Arkin precipitation pentad data and National Centers for Environmental Prediction daily reanalysis data focusing on the period 21 May to 28 August, which covers the prominent life cycle of the ASM. The first mode, representing the seasonal cycle, explains about 20%–40% of the total variability in the parameters considered in the study. The pronounced feature in the present study is that the seasonal evolution of the sea level pressure anomaly contrast between the Asian continent and the surrounding oceans is the governing mechanism for the ASM evolution. The northward migration of the low pressure anomaly from the Indian Ocean and the moisture transport by a low-level westerly (Somali jet) toward India describes the evolution of the precipitation field ov...