[ { "id": "authors:b97qa-s5640", "collection": "authors", "collection_id": "b97qa-s5640", "cite_using_url": "https://authors.library.caltech.edu/records/b97qa-s5640", "type": "article", "title": "Response Theory via Generative Score Modeling", "author": [ { "family_name": "Giorgini", "given_name": "Ludovico Theo", "orcid": "0000-0003-1641-9087" }, { "family_name": "Deck", "given_name": "Katherine", "orcid": "0009-0001-0572-7642", "clpid": "Deck-Katherine-M" }, { "family_name": "Bischoff", "given_name": "Tobias", "orcid": "0000-0003-3930-2762", "clpid": "Bischoff-Tobias" }, { "family_name": "Souza", "given_name": "Andre", "orcid": "0000-0001-8025-3558" } ], "abstract": "

We introduce an approach for analyzing the responses of dynamical systems to external perturbations that combines score-based generative modeling with the generalized fluctuation-dissipation theorem. The methodology enables accurate estimation of system responses, including those with non-Gaussian statistics. We numerically validate our approach using time-series data from three different stochastic partial differential equations of increasing complexity: an Ornstein-Uhlenbeck process with spatially correlated noise, a modified stochastic Allen-Cahn equation, and the 2D Navier-Stokes equations. We demonstrate the improved accuracy of the methodology over conventional methods and discuss its potential as a versatile tool for predicting the statistical behavior of complex dynamical systems.

", "doi": "10.1103/physrevlett.133.267302", "issn": "0031-9007", "publisher": "American Physical Society", "publication": "Physical Review Letters", "publication_date": "2024-12-31", "series_number": "26", "volume": "133", "issue": "26", "pages": "267302" }, { "id": "authors:xhesv-wv708", "collection": "authors", "collection_id": "xhesv-wv708", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20230818-791138000.1", "type": "article", "title": "The Importance of Hyperspectral Soil Albedo Information for Improving Earth System Model Projections", "author": [ { "family_name": "Braghiere", "given_name": "R. K.", "orcid": "0000-0002-7722-717X", "clpid": "Kerches-Braghiere-Renato" }, { "family_name": "Wang", "given_name": "Y.", "orcid": "0000-0002-3729-2743", "clpid": "Wang-Yujie" }, { "family_name": "Gagn\u00e9\u2010Landmann", "given_name": "A.", "clpid": "Gagn\u00e9\u2010Landmann-A" }, { "family_name": "Brodrick", "given_name": "P. G.", "orcid": "0000-0001-9497-7661", "clpid": "Brodrick-Philip-G" }, { "family_name": "Bloom", "given_name": "A. A.", "orcid": "0000-0002-1486-1499", "clpid": "Bloom-A-Anthony" }, { "family_name": "Norton", "given_name": "A. J.", "orcid": "0000-0001-7708-3914", "clpid": "Norton-Alexander-J" }, { "family_name": "Ma", "given_name": "S.", "orcid": "0000-0002-6494-724X", "clpid": "Ma-Shuang" }, { "family_name": "Levine", "given_name": "P.", "orcid": "0000-0002-1248-6920", "clpid": "Levvine-Paul" }, { "family_name": "Longo", "given_name": "M.", "orcid": "0000-0001-5062-6245", "clpid": "Longo-Marcos" }, { "family_name": "Deck", "given_name": "K.", "clpid": "Deck-Katherine-M" }, { "family_name": "Gentine", "given_name": "P.", "orcid": "0000-0002-0845-8345", "clpid": "Gentine-Pierre" }, { "family_name": "Worden", "given_name": "J. R.", "orcid": "0000-0003-0257-9549", "clpid": "Worden-John-R" }, { "family_name": "Frankenberg", "given_name": "C.", "orcid": "0000-0002-0546-5857", "clpid": "Frankenberg-C" }, { "family_name": "Schneider", "given_name": "T.", "orcid": "0000-0001-5687-2287", "clpid": "Schneider-T" } ], "abstract": "AbstractEarth system models (ESMs) typically simplify the representation of land surface spectral albedo to two values, which correspond to the photosynthetically active radiation (PAR, 400\u2013700\u00a0nm) and the near infrared (NIR, 700\u20132,500\u00a0nm) spectral bands. However, the availability of hyperspectral observations now allows for a more direct retrieval of ecological parameters and reduction of uncertainty in surface reflectance. To investigate sensitivity and quantify biases of incorporating hyperspectral albedo information into ESMs, we examine how shortwave soil albedo affects surface radiative forcing and simulations of the carbon and water cycles. Results reveal that the use of two broadband values to represent soil albedo can introduce systematic radiative\u2010forcing differences compared to a hyperspectral representation. Specifically, we estimate soil albedo biases of \u00b10.2 over desert areas, which can result in spectrally integrated radiative forcing divergences of up to 30\u00a0W\u00a0m\u207b\u00b2, primarily due to discrepancies in the blue (404\u2013504\u00a0nm) and far\u2010red (702\u2013747\u00a0nm) regions. Furthermore, coupled land\u2010atmosphere simulations indicate a significant difference in net solar flux at the top of the atmosphere (>3.3\u00a0W\u00a0m\u207b\u00b2), which can impact global energy fluxes, rainfall, temperature, and photosynthesis. Finally, simulations show that considering the hyperspectrally resolved soil reflectance leads to increased maximum daily temperatures under current and future CO\u2082 concentrations.", "doi": "10.1029/2023av000910", "issn": "2576-604X", "publisher": "American Geophysical Union", "publication": "AGU Advances", "publication_date": "2023-08", "series_number": "4", "volume": "4", "issue": "4", "pages": "Art. No. e2023AV000910" }, { "id": "authors:0z6y9-k7e09", "collection": "authors", "collection_id": "0z6y9-k7e09", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170222-103759123", "type": "article", "title": "Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1", "author": [ { "family_name": "Gillon", "given_name": "Micha\u00ebl", "orcid": "0000-0003-1462-7739", "clpid": "Gillon-Micha\u00ebl" }, { "family_name": "Deck", "given_name": "Katherine M.", "clpid": "Deck-Katherine-M" }, { "family_name": "Ingalls", "given_name": "James G.", "orcid": "0000-0003-4714-1364", "clpid": "Ingalls-James-G" }, { "family_name": "Carey", "given_name": "Sean J.", "orcid": "0000-0002-0221-6871", "clpid": "Carey-Sean-J" } ], "abstract": "One aim of modern astronomy is to detect temperate, Earth-like exoplanets that are well suited for atmospheric characterization. Recently, three Earth-sized planets were detected that transit (that is, pass in front of) a star with a mass just eight per cent that of the Sun, located 12 parsecs away. The transiting configuration of these planets, combined with the Jupiter-like size of their host star\u2014named TRAPPIST-1\u2014makes possible in-depth studies of their atmospheric properties with present-day and future astronomical facilities. Here we report the results of a photometric monitoring campaign of that star from the ground and space. Our observations reveal that at least seven planets with sizes and masses similar to those of Earth revolve around TRAPPIST-1. The six inner planets form a near-resonant chain, such that their orbital periods (1.51, 2.42, 4.04, 6.06, 9.1 and 12.35 days) are near-ratios of small integers. This architecture suggests that the planets formed farther from the star and migrated inwards. Moreover, the seven planets have equilibrium temperatures low enough to make possible the presence of liquid water on their surfaces.", "doi": "10.1038/nature21360", "pmcid": "PMC5330437", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "2017-02-23", "series_number": "7642", "volume": "542", "issue": "7642", "pages": "456-460" }, { "id": "authors:jagn4-3j817", "collection": "authors", "collection_id": "jagn4-3j817", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160427-085910052", "type": "article", "title": "Secure mass measurements from transit timing: 10 Kepler exoplanets between 3 and 8 M_\u2295 with diverse densities and incident fluxes", "author": [ { "family_name": "Jontof-Hutter", "given_name": "Daniel", "orcid": "0000-0002-6227-7510", "clpid": "Jontof-Hutter-Daniel" }, { "family_name": "Ford", "given_name": "Eric B.", "orcid": "0000-0001-6545-639X", "clpid": "Ford-Eric-B" }, { "family_name": "Rowe", "given_name": "Jason F.", "orcid": "0000-0002-5904-1865", "clpid": "Rowe-Jason-F" }, { "family_name": "Lissauer", "given_name": "Jack J.", "orcid": "0000-0001-6513-1659", "clpid": "Lissauer-Jack-J" }, { "family_name": "Fabrycky", "given_name": "Daniel C.", "orcid": "0000-0003-3750-0183", "clpid": "Fabrycky-Daniel-C" }, { "family_name": "Van Laerhoven", "given_name": "Christa", "clpid": "Van-Laerhoven-Christa" }, { "family_name": "Agol", "given_name": "Eric", "orcid": "0000-0002-0802-9145", "clpid": "Agol-Eric" }, { "family_name": "Deck", "given_name": "Katherine M.", "clpid": "Deck-Katherine-M" }, { "family_name": "Holczer", "given_name": "Tomer", "clpid": "Holczer-Tomer" }, { "family_name": "Mazeh", "given_name": "Tsevi", "clpid": "Mazeh-Tsevi" } ], "abstract": "We infer dynamical masses in eight multiplanet systems using transit times measured from Kepler's complete data set, including short-cadence data where available. Of the 18 dynamical masses that we infer, 10 pass multiple tests for robustness. These are in systems Kepler-26 (KOI-250), Kepler-29 (KOI-738), Kepler-60 (KOI-2086), Kepler-105 (KOI-115), and Kepler-307 (KOI-1576). Kepler-105 c has a radius of 1.3 R_\u2295 and a density consistent with an Earth-like composition. Strong transit timing variation (TTV) signals were detected from additional planets, but their inferred masses were sensitive to outliers or consistent solutions could not be found with independently measured transit times, including planets orbiting Kepler-49 (KOI-248), Kepler-57 (KOI-1270), Kepler-105 (KOI-115), and Kepler-177 (KOI-523). Nonetheless, strong upper limits on the mass of Kepler-177 c imply an extremely low density of ~0.1 g cm^(\u22123). In most cases, individual orbital eccentricities were poorly constrained owing to degeneracies in TTV inversion. For five planet pairs in our sample, strong secular interactions imply a moderate to high likelihood of apsidal alignment over a wide range of possible eccentricities. We also find solutions for the three planets known to orbit Kepler-60 in a Laplace-like resonance chain. However, nonlibrating solutions also match the transit timing data. For six systems, we calculate more precise stellar parameters than previously known, enabling useful constraints on planetary densities where we have secure mass measurements. Placing these exoplanets on the mass\u2013radius diagram, we find that a wide range of densities is observed among sub-Neptune-mass planets and that the range in observed densities is anticorrelated with incident flux.", "doi": "10.3847/0004-637X/820/1/39", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2016-03-20", "series_number": "1", "volume": "820", "issue": "1", "pages": "Art. No. 39" } ]