High-mountain lakes are unique ecosystems with very few examples at tropical latitudes for experimentation. A two-year, high-frequency meteorological and water-column dataset from the crater of the Nevado de Toluca volcano, in Mexico, at an altitude of about 4200 m above sea level, allowed for the study of temporal changes in the thermal structure, water level, and water balance in the Lakes El Sol and La Luna, separated by about 500 m by a lava dome. Annual fluctuations in the water level of the lakes and calculations of the annual variability of the water balance showed that the lakes accumulated almost four times less water from rainfall than expected. Furthermore, the temperature measured at a depth of 15 cm in the bottom sediments of Lake El Sol revealed an unexpected warming during the cold season. Estimated heat fluxes through the lake bottom were less than 0.3 W m⁻² during the winter and less than 0.1 W m⁻² during the rest of the year. Although the variability of the hydrometeorological regime of high-mountain lakes remains relatively poorly understood, our results significantly improve the understanding of these complex processes of stratification and mixing in these unique lake ecosystems.

The Gulf of California has many regions of potential tidal-stream energy that have been identified and characterized using in-situ measurements and numerical ocean models. The Midriff Islands region has received particular attention due to its increased current speeds and high kinetic energy. This increase in energy can be seen in the formation of internal wave packets propagating for several hundred kilometers. Here we present a brief description of internal wave measurements travel towards the Northern Gulf and explore energy generation sites. In this paper we characterize the tidal inflow and outflow that passes throughout the Midriff Islands in the central part of the Gulf. We use a three-dimensional numerical ocean model that adequately reproduces the tidal flow and the increase in speed and kinetic energy between the islands. The current flow structure shows the highest velocity cores near the shore and far from the bottom. During the rising tide, the maximum current flow (~0.6 ms⁻¹) was found between Turón Island and San Lorenzo Island, from the surface to 200 m depth. When the currents flowed out of the Gulf, during the falling tide, the maximum negative current (−0.8 ms⁻¹) was found between Tiburon Island and Turón Island, from near the surface to 80 m depth. Although there are favorable conditions for power generation potential by tidal flows, the vertical variability of the current must be considered for field development and equipment installation sites.

We use 29 years of altimeter-derived sea level anomalies and geostrophic velocities (1993–2021) from the Copernicus Marine Service to identify the Mexican Coastal Current (MCC) and to examine how it interacts with the coastline. Variance-ellipse and empirical orthogonal function analyses isolate a narrow alongshore jet with a mean width of about 95 km and average speeds near 0.3 m ${\mathrm{s}}^{-1}$ that reverses direction semiannually: poleward in June and July and equatorward in the rest of the year. When the MCC impinges on broad concavities in the coast, the boundary layer separates, forming recirculation cells that intensify and detach as coherent eddies. These near-shore eddies have similar radii (from ∼30 km) and relative vorticity of $\pm 0.5\times {10}^{-5}$${\mathrm{s}}^{-1}$ at the beginning of their generation, and they propagate offshore once the current weakens. A simple numerical model reproduces the observed behavior and suggests that eddy formation is controlled by flow separation rather than generic instability. The semiannual change in direction of the MCC indicate a link with the larger-scale North Equatorial Countercurrent and Costa Rica Coastal Current systems of the eastern tropical Pacific.

We are concerned with the mathematical and numerical modeling of hydrodynamic processes in the Gulf of California. The dynamic is driven by a forcing tide producing an inflow and outflow from the mouth of the Gulf to the northernmost part. When the tidal flow passes through the area of the Islands in the central part of the Gulf, it channels, increasing its speed. On the San Esteban Sill, a hydraulic jump is formed, then internal waves and solitons are released. Based on observational field campaigns, and hydrostatic 3D modeling, it is claimed that this is a cause–effect phenomenon. Hydrostatic models are unable to produce the groups of soliton-like waves. Consequently, we develop a non-hydrostatic version, a 2D vertical-slice model with the inclusion of density effects. Its hydrographic characteristics, such as stratification and bathymetric features, are modeled with appropriate initial and boundary conditions. The numerical solution is by a pressure projection method. The method is tested on benchmark problems and then applied to the Gulf of California. The data of the observational field campaigns are satisfactorily reproduced by the numerical results.

In this work, we investigate if it is possible to identify the Mexican coastal current using satellite data and how this coastal current interacts with the coastline. This study is carried out using the mean sea level anomaly and derived geostrophic velocities from the Copernicus Marine Service from 1993 to 2021. By computing variance ellipses and empirical orthogonal functions for the ocean velocity data, we were able to identify and delineate the coastal current and determine its main characteristics: an average width of 95 km and an average velocity of 0.3 m s^-1. The preferred direction of this coastal current is parallel to the coast, with episodes towards the pole and towards the equators showing seasonal variability. Using a 3D numerical model, we found that the interaction of the coastal current with the coastline generates eddies near the coast in some places forming a wide concavity. The eddies are formed while the current is present (poleward or equatorward), become intense, and move away from the coast until the current weakens. The statistics of some physical variables of near-shore eddies show that they have a similar radius of 30 km and a vorticity of 0.5 X 10^-5 s^-1. We conclude that there is a large number of eddies in the coastal zone of the Mexican Tropical Pacific, and some of these eddies are formed by the interaction of the coastal current with the coast.

In this work, we investigate if it is possible to identify the Mexican coastal current using satellite data and how this coastal current interacts with the coastline. This study is carried out using the mean sea level anomaly and derived geostrophic velocities from the Copernicus Marine Service from 1993 to 2021. By computing variance ellipses and empirical orthogonal functions for the ocean velocity data, we were able to identify and delineate the coastal current and determine its main characteristics: an average width of 95 km and an average velocity of 0.3 m s^-1. The preferred direction of this coastal current is parallel to the coast, with episodes towards the pole and towards the equators showing seasonal variability. Using a 3D numerical model, we found that the interaction of the coastal current with the coastline generates eddies near the coast in some places forming a wide concavity. The eddies are formed while the current is present (poleward or equatorward), become intense, and move away from the coast until the current weakens. The statistics of some physical variables of near-shore eddies show that they have a similar radius of 30 km and a vorticity of 0.5 X 10^-5 s^-1. We conclude that there is a large number of eddies in the coastal zone of the Mexican Tropical Pacific, and some of these eddies are formed by the interaction of the coastal current with the coast.