Presentation Details
| On the Importance of Parallax Effects in Satellite to Irradiance Modeling Richard Perez1, 2, Marc Perez1, Andrew Foster1, Jing Huang1, Maina André3, Raphël Cécé3. 1Clean Power Research, Bellevue, WA, USA.2SUNY Albany, Albany, NY, USA.3Université des Antilles, Pointe-à-Pitre, Guadeloupe |
Abstract
Advances in geostationary satellite imagery now enable solar irradiance models to operate at sub‑kilometer spatial and sub‑10‑minute temporal resolution, exposing errors previously masked at coarse scales. One such error, parallax displacement of clouds relative to ground locations, has long been considered negligible. This study shows that parallax becomes a first‑order source of bias in microclimates with preferential cloud formation, such as tropical islands and mountain‑adjacent regions. Using five years of ground‑measured global horizontal irradiance (GHI) from eight stations in Guadeloupe and Martinique, we compare observations to high‑resolution satellite‑derived GHI. Results reveal systematic diurnal bias patterns (up to +25%) linked to parallax and shadow mis‑collocation, particularly at orographic sites. We outline a geometry‑based correction method incorporating satellite view angle, solar position, and cloud‑top height, offering a practical pathway to improve model accuracy without extensive ground adaptation. Explicit geometric correction emerges as the most portable and robust solution. These findings underscore the need to revisit assumptions in next‑generation solar resource assessment, especially for regions with complex cloud dynamics.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.