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首页> 外文学位 >Application de la teledetection a l'analyse de la variabilite climatique des regions boreales et subarctiques du Canada et a la validation du modele regional canadien du climat (French text).
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Application de la teledetection a l'analyse de la variabilite climatique des regions boreales et subarctiques du Canada et a la validation du modele regional canadien du climat (French text).

机译：遥感在加拿大北方和北极地区的气候变化分析中的应用，以及在加拿大地区气候模型的验证中的应用（法文）。

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The subject of the present thesis fits within the scope of global climate change analysis. It focuses on two main areas of interest, namely the study of recent past climate over the last few decades and the development of tools for modeling future climate.; Study of past climate. The first part of this thesis deals with the interpretation of NOAA-AVHRR (National Oceanic and Atmospheric Administration - Advanced Very High Resolution Radiometer) time series at the continental spatial scale. The data constitute an archive of decadal or weekly composite spanning over two decades which was developed for studying and monitoring boreal ecosystem activity in Canada. This study uses classical parameters derived from remote sensing in the visible and thermal infrared spectra (NDVI vegetation activity index, land-surface temperature Ts), as well as indicators chosen for their robustness. The latter parameters (length of the growing season, annual growing degree-days, and ecotone displacement) were selected so as to minimize problems related to instrumental drift and inter-satellite adjustment. The study of the twenty year NOAA-AVHRR satellite archives, permitted the observation of recent climate variations. There were compared with daily meteorological surveys of temperature and precipitation as well as with the length of the snow cover period. It was possible to observe rapid cycle climatic phenomena such as the El Niño/La Niña couple whose effect on surface temperature and the length of the growing season was found to be more significant over the central region of Canada. The NAO (North Atlantic Oscillation) and AO (Arctic Oscillation) oscillations were also found to have an influence on the climatic regime of Canada. The effects of these climatic cycles on the annual growing degree-days are more accentuated over the Northeastern region of Canada in spring. Significant climatic trends over the last twenty years were also observed. We demonstrated, based on the use of the indicators developed in this thesis, a North/South disparity over Canada. The region north of the 55th parallel indicated a warming trend (increase in the annual degree-days, reduction in the length of the snow cover period, increase in the length of the growing season, increase in the air temperature), southern regions of Canada appeared to be cooling (based on the same indicators).; Validation of the Canadian regional climate model ( towards the development of future climate prediction tools). The second part of this thesis focuses on the validation, using remotely sensed measurements, of a specific surface field of the CRCM model (Canadian Regional Climate Model), namely the land-surface temperature. The comparison over a short time scale between the ground temperature values modeled by the CRCM with composited satellite temperatures shows the feasibility of validating climatic models using remote sensing. The results show a slight under-estimation of the CRCM ground temperature during the summer. This is possibly due to an overestimation of the precipitation rate which in turn generates excessive surface wetness and an excessive evaporation rate (thus cooling the surface). The agreement which was observed between model and measurements strongly suggest that climate models of the type used in this work should facilitate reliable predictions of future climate trends and help in orienting the decision making process for the world community as we collectively fact the prospect of climate imbalance.
机译：本论文的主题符合全球气候变化分析的范围。它侧重于两个主要感兴趣的领域，即对过去几十年中最近的过去气候的研究以及对未来气候进行建模的工具的开发。 过去气候的研究。本文的第一部分是对大陆空间尺度上的NOAA-AVHRR（国家海洋和大气管理局-先进超高分辨率辐射计）时间序列的解释。这些数据构成了过去二十年中十年或每周一次的综合资料的档案，该档案是为研究和监测加拿大的北方生态系统活动而开发的。这项研究使用了从可见光和热红外光谱（NDVI植被活动指数，地表温度Ts）中的遥感数据得出的经典参数，以及因其坚固性而选择的指标。选择后一个参数（生长季节的长度，年生度-天数和过渡带位移），以使与仪器漂移和卫星间调整有关的问题最小化。对二十年来的NOAA-AVHRR卫星档案进行的研究允许观察最近的气候变化。将其与每日气象调查的温度和降水以及积雪期的长度进行了比较。可以观察到快速的循环气候现象，例如厄尔尼诺/拉尼娜对，它们在加拿大中部地区对地表温度和生长期的影响更为显着。还发现NAO（北大西洋涛动）和AO（北极涛动）的振荡对加拿大的气候状况有影响。这些气候周期对年度增长日数的影响在春季的加拿大东北地区更为突出。在过去的二十年中，还观察到了重要的气候趋势。基于使用本文中开发的指标，我们证明了加拿大的南北差距。第55 平行线以北区域显示出变暖趋势（年度日数增加，积雪期长度减少，生长期增加，空气温度），加拿大南部地区似乎正在降温（基于相同的指标）。 验证加拿大区域气候模型（对未来气候预测工具的开发）。本文的第二部分着重于使用遥感测量方法对CRCM模型（加拿大区域气候模型）的特定表面场，即地表温度进行验证。通过CRCM建模的地面温度值与合成的卫星温度之间的短时尺度比较，表明使用遥感验证气候模型的可行性。结果表明，夏季CRCM地面温度略有低估。这可能是由于过高估计了沉淀速率，而沉淀速率又产生了过多的表面湿度和过多的蒸发速率（从而冷却了表面）。在模型和测量结果之间观察到的一致性强烈表明，在这项工作中使用的那种气候模型应该有助于对未来气候趋势进行可靠的预测，并有助于确定国际社会的决策过程，因为我们共同认为气候失衡的前景。

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