Different types of mass flow-like movements are often triggered by rainfall in the same mountain basin in different seasons of the year, ranging from debris flows to hyper-concentrated flows and flash floods. Despite some similarities, such as large runout and high velocity, these natural hazards are different in their propagation mechanisms. Landslide mass and materials eroded along the path may be deposited along the channel(s) and subsequently remobilised; in other cases, runoff and debris mix inside the channels or nearby the protective structures. Such combined processes are typical along the northern Italian Alps but also in steep catchments in Liguria, Campania and Calabria regions. In this work, a two-phase mathematical framework is adopted to simulate the propagation of solid and water mixtures along a 3D terrain model. The mass and momentum conservation equations are solved by including the rheological behaviour models of the materials involved: frictional for soil, Newtonian for water. Selected scenarios are presented for a case study in Southern Italy with a discussion provided on how solid concentration of flow-like mass movements evolves in a mountain catchment. Numerical results show that at first, the runoff water accumulated within the natural channels and then a debris flow propagated rapidly down the slope meanwhile the concentration of solid material decreased due to the addition of runoff water and a hyperconcentrated flow reached the foothill area, later even more diluted and capable to move several kilometres far until it almost reached a railway line.

To enhance the path-tracking accuracy of unmanned articulated road roller (UARR) operating on low-adhesion, slippery surfaces, this paper proposes a hierarchical cascaded control (HCC) architecture integrated with real-time ground adhesion coefficient estimation. Addressing the complex nonlinear dynamics between the two rigid bodies of the vehicle and its interaction with the ground, an upper-layer nonlinear model predictive controller (NMPC) is designed. This layer, based on a 4-degree-of-freedom (4-DOF) dynamic model, calculates the required steering torque using position and heading errors. The lower layer employs a second-order sliding mode controller (SOSMC) to precisely track the steering torque and output the corresponding steering wheel angle. To accommodate the anisotropic and time-varying nature of slippery surfaces, a strong-tracking unscented Kalman filter (ST-UKF) observer is introduced for ground adhesion coefficient estimation. By dynamically adjusting the covariance matrix, the observer reduces reliance on historical data while increasing the weight of new data, significantly improving real-time estimation accuracy. The estimated adhesion coefficient is fed back to the upper-layer NMPC, enhancing the control system's adaptability and robustness under slippery conditions. The HCC is validated through simulation and real-vehicle experiments and compared with LQR and PID controllers. The results demonstrate that HCC achieves the fastest response time and smallest steady-state error on both dry and slippery gravel soil surfaces. Under slippery conditions, while control performance decreases compared to dry surfaces, incorporating ground adhesion coefficient observation reduces steady-state error by 20.62%.

Third Pole natural cascade alpine lakes (NCALs) are exceptionally sensitive to climate change, yet the underlying cryosphere-hydrological processes and associated societal impacts are largely unknown. Here, with a state-of-the-art cryosphere-hydrology-lake-dam model, we quantified the notable high-mountain Hoh-Xil NCALs basin (including Lakes Zonag, Kusai, Hedin Noel, and Yanhu, from upstream to downstream) formed by the Lake Zonag outburst in September 2011. We demonstrate that long-term increased precipitation and accelerated ice and snow melting as well as short-term heavy precipitation and earthquake events were responsible for the Lake Zonag outburst; while the permafrost degradation only had a marginal impact on the lake inflows but was crucial to lakeshore stability. The quadrupling of the Lake Yanhu area since 2012 was due to the tripling of inflows (from 0.25 to 0.76 km(3)/year for 1999 to 2010 and 2012 to 2018, respectively). Prediction of the NCALs changes suggests a high risk of the downstream Qinghai-Tibet Railway, necessitating timely adaptions/mitigations.

Light absorbing particles (LAPs) include black carbon (BC) and mineral dust and are of interest due to their positive radiative forcing and contribution to albedo reductions and snow and glacier melt. This study documents historic BC and dust deposition as well as their effect on albedo on South Cascade Glacier (SCG) in Washington State (USA) through the analysis of a 158-m (139.5-m water equivalent [w.e.]) ice core extracted in 1994 and spanning the period 1840-1991. Peak BC deposition occurred between 1940 and 1960, when median BC concentrations were 16 times higher than background, likely dominated by domestic coal and forest fire emissions. Post 1960 BC concentrations decrease, followed by an increase from 1977 to 1991 due to melt consolidation and higher emissions. Differences between the SCG record and BC emission inventories, as well as ice core records from other regions, highlight regional differences in the timing of anthropogenic and biomass BC emissions. Dust deposition on SCG is dominated by local sources and is variable throughout the record. Albedo reductions from LAP are dominated by dust deposition, except during high BC deposition events from forest fires and during 1940-1960 when BC and dust similarly contribute to albedo reductions. This study furthers understanding of the factors contributing to historical snowmelt and glacier retreat in the Cascades and demonstrates that ice cores retrieved from temperate glaciers have the potential to provide valuable records of LAP deposition. Plain Language Summary Light absorbing particles (LAPs) include black carbon (BC, i.e., soot) produced by the incomplete combustion of fossil and biofuels and mineral dust. In the atmosphere, LAP can lead to atmospheric warming, while LAP deposited on snow and glaciers causes darkening, leading to increased solar energy absorption, warming, and faster melt. The role of LAP in climate change is a large source of uncertainty because LAP emissions and deposition are spatially and temporally heterogeneous. We used an ice core retrieved from South Cascade Glacier in Washington State (USA) to reconstruct BC and dust deposition. BC deposition between 1940-1960 is 16 times higher than during the preindustrial period, likely dominated by domestic coal and forest fire emissions. Differences between the SCG ice core and BC emission inventories, as well as ice cores from other regions, highlight regional differences in BC emissions from humans and forest fires. Dust is a larger contributor to snow darkening than BC, except during high BC deposition events from forest fires and during the 1940-1960 period when BC and dust contribute comparably. This study furthers understanding of the role of BC and dust in snow and glacier melt in the Washington Cascades.

Global efforts to mitigate climate change have largely focused on reducing emissions of carbon dioxide (CO2), which is responsible for 55-60% of current anthropogenic radiative forcing on warming impact. Because of its long lifetime (similar to 130 years [1]) in the atmosphere, long-lasting CO2 will remain the primary driver of long-term temperature rise even if new CO2 emissions dropped to zero. A fast-action climate mitigation strategies is therefore strongly needed to provide more sizeable short-term benefits than CO2 reductions by reducing emission of short-lived climate pollutants (SLCPs), having atmospheric lifetimes of less than 20 years [2], which would allow for short-term drops in atmospheric concentrations and hence slow climate change over the next several decades. Monitoring of climatically and environmentally active SLCPs is important not only for policy-based reporting, but also for basic process-based understanding of climate related processes in the atmosphere. In this talk, we will overview our recent progress in the developments and applications of laserbased optical instruments for the measurements of environmental and livestock emitted methane (CH4), as well as the measurement of black carbon (BC) absorption. The experimental detail, the preliminary measurement results, the corresponding data processing and analysis will be presented.