Modeling of Seasonal Lake Level Fluctuations of Titan's Seas/Lakes

Tokano, Tetsuya; Lorenz, Ralph D.

doi:10.1029/2018je005898

Cited by 7 publications

(5 citation statements)

References 49 publications

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“…At Vid Flumina, where it is possible to estimate drainage basin area, the estimated discharge implies runoff rates of M > 0.04–5.2 mm/h. Permitting losses to infiltration and evaporation ( 51 ), the lower end of this range is consistent with climate models ( 52 , 53 ), which predict precipitation rates of ~0.001–0.1 mm/h for yearly storms.…”

Section: Resultssupporting

confidence: 81%

Reconstructing river flows remotely on Earth, Titan, and Mars

Birch

Parker

Corlies

et al. 2023

Proc. Natl. Acad. Sci. U.S.A.

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Alluvial rivers are conveyor belts of fluid and sediment that provide a record of upstream climate and erosion on Earth, Titan, and Mars. However, many of Earth’s rivers remain unsurveyed, Titan’s rivers are not well resolved by current spacecraft data, and Mars’ rivers are no longer active, hindering reconstructions of planetary surface conditions. To overcome these problems, we use dimensionless hydraulic geometry relations—scaling laws that relate river channel dimensions to flow and sediment transport rates—to calculate in-channel conditions using only remote sensing measurements of channel width and slope. On Earth, this offers a way to predict flow and sediment flux in rivers that lack field measurements and shows that the distinct dynamics of bedload-dominated, suspended load-dominated, and bedrock rivers give rise to distinct channel characteristics. On Mars, this approach not only predicts grain sizes at Gale Crater and Jezero Crater that overlap with those measured by the Curiosity and Perseverance rovers, it enables reconstructions of past flow conditions that are consistent with proposed long-lived hydrologic activity at both craters. On Titan, our predicted sediment fluxes to the coast of Ontario Lacus could build the lake’s river delta in as little as ~1,000 y, and our scaling relationships suggest that Titan’s rivers may be wider, slope more gently, and transport sediment at lower flows than rivers on Earth or Mars. Our approach provides a template for predicting channel properties remotely for alluvial rivers across Earth, along with interpreting spacecraft observations of rivers on Titan and Mars.

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Section: Resultssupporting

confidence: 81%

Reconstructing river flows remotely on Earth, Titan, and Mars

Birch

Parker

Corlies

et al. 2023

Proc. Natl. Acad. Sci. U.S.A.

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“…The lake evaporation rate per unit area is calculated as a function of lake temperature, wind speed, and air humidity (Tokano & Lorenz, ). Evaporation is assumed to stop during rainfall because of the high near‐surface air humidity.…”

Section: Methodsmentioning

confidence: 99%

Stable Existence of Tropical Endorheic Lakes on Titan

Tokano

2020

Geophysical Research Letters

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Cassini detected numerous hydrocarbon seas/lakes in the polar region of Titan and wide areas of sand seas in the tropical region, which initially led to the perception that Titan's tropical region may be too dry for lakes. Yet, a few tropical lakes were possibly seen on Cassini's near‐infrared images, while they were not seen by other imaging instruments. This study shows by a lake balance model in combination with a global climate model and global topography map that a few lakes can perennially exist in Titan's tropical drainage basins of Shangri‐La, Tui Regio, and Hotei Regio. This is possible because the lakes are fed by precipitation in a huge catchment area, while efficient lake evaporation occurs only in a small area inside of deep topographic depressions. However, tropical lakes may occasionally desiccate due to orbitally forced changes in tropical precipitation.

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“…The vine copula simulation method was compared with two other models, a BPNN and an SVR, to evaluate the accuracy of the forecasted lake water levels. The model's ability to predict the water level of Erhai Lake was evaluated using four common statistical indices of error, namely, the mean error (ME), root mean square error (RMSE), index of agreement (IA), and Nash-Sutcliffe efficiency coefficient (NSE), that were calculated with formulae ( 5)- (8). The IA values are between 0-1, and the model performance improves as the IA value increases.…”

Section: Model Error Evaluationmentioning

confidence: 99%

Developing a vine copula model to simulate and predict long serial lake water levels

Wei

Jing

et al. 2023

E3S Web of Conf.

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Lake water level changes show randomness and the complexity of basin hydrological simulation and lake water level response. We constructed a vine copula model to simulate and predict lake water level that incorporated rolling decisions and real-time correction of prediction results. The model was applied to predict the long- and short-term water levels in Erhai Lake on the Yun-gui Plateau, southwest China. The results showed that (1) the predicted daily water levels (with ME=0.02~0.09, RMSE=0.02~0.024, NSE=0.99, and IA=0.99) were more accurate than the predicted monthly water levels (with the ME=0.039~0.444, RMSE=0.194~0.279, NSE=0.913~0.958, and IA=0.977~0.989), and the accuracy of the predictions improved as the number of variables increased. (2) The vine copula model outperformed the back-propagation neural network and support vector regression models, and, of the three model types, gave the best estimate of the nonlinear relationships between the predicted water level and climatic factors, especially in the wet season (May to October). (3) The prediction accuracy of the vine copula model was lower for small sample sizes and when there was a lack of runoff data. By improving the analysis of the model’s errors, the percentages of the relative errors of the prediction accuracy less than 5%, 10%, 15%, and 20% increased to 70%, 83%, 95%, and 98%, respectively.

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Modeling of Seasonal Lake Level Fluctuations of Titan's Seas/Lakes

Cited by 7 publications

References 49 publications

Reconstructing river flows remotely on Earth, Titan, and Mars

Reconstructing river flows remotely on Earth, Titan, and Mars

Stable Existence of Tropical Endorheic Lakes on Titan

Developing a vine copula model to simulate and predict long serial lake water levels

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