Current Research on Geography, Earth Science and Environment Vol. 10

The Multi-Scale Dynamics of an Extreme Precipitation Event in Chicago: Observations of Environment-Lake Breeze-Convection Interactions

Michael L. Kaplan, Md Shamimul Hasan, Yuh-Lang Lin — Tue, 29 Sep 2026 00:00:00 +0000

On 2 July 2023, a destructive, two-stage extreme precipitation event produced approximately 225 mm (9 in) of rainfall in less than 12 hours within a narrow corridor between O’Hare and Midway Airports in Chicago. Understanding how synoptic, mesoscale, lake-breeze, and convective processes combined to focus this rainfall is important for improving forecasts and flood preparedness in densely populated urban regions. This study aims to identify the multiscale dynamical and thermodynamic processes that organized the event before considering any urban enhancement. It also examines how three quasi-linear convective systems (QLCSs) interacted and evolved into a larger mesoscale convective system with mesoscale convective vortex (MCV) characteristics. The analysis uses ERA5 reanalysis, 13-km Rapid Refresh (RAP) analyses, Storm Prediction Center diagnostic fields, upper-air soundings, Chicago-area surface and Lake Michigan buoy observations, and NOAA NEXRAD radar data. These datasets are examined across meso-alpha to meso-gamma scales to diagnose the evolving jet-streak circulation, potential-vorticity structure, moisture transport, instability, surface convergence, and convective organization. The precursor environment featured an upstream deep cold trough, a mid-to-upper-tropospheric jet streak with coupled potential-vorticity maxima, a stationary warm boundary and deformation zone, and a west-southwesterly low-level jet that transported abundant moisture towards northern Illinois. The first rainfall stage developed as three QLCSs interacted over Chicago and formed a T-bone convective structure near Midway Airport, whereas the second stage followed upscale growth into a long-lived MCV-like circulation with persistent wraparound stratiform precipitation. These linked processes concentrated extreme rainfall over a small urban corridor even before urban heat-island and drag effects were isolated. The results show that extreme urban flooding can arise from close coupling among larger-scale atmospheric forcing, Lake Michigan-related convergence, and local convective evolution. Operational forecasters should therefore monitor transitions between jet-streak forcing regions, low-level moisture and convergence corridors, interacting QLCSs, and emerging T-bone or vortical radar structures. Incorporating these signals into warning operations and urban flood-preparedness planning may improve early recognition of localized, high-impact rainfall events.

Digital Integration in Soil Carbon Sequestration: A Critical Appraisal of Measurement, Reporting, Verification and Permanence Frontiers

Kanav Sharma, Banti, Shita, Shingare Mahesh Namdev — Tue, 29 Sep 2026 00:00:00 +0000

Soil organic carbon (SOC) sequestration in managed land occupies an unusual position in climate policy. The biogeochemical rationale is well established, yet the quantitative claims made on its behalf are settled not in the soil but in the measurement, reporting and verification (MRV) systems that convert soil processes into tradable or reportable units. Over the past decade these systems have been reconstructed around digital components, including soil spectroscopy, satellite reflectance compositing, machine learning prediction, process-based simulation, data assimilation and distributed ledger infrastructures. This review critically appraises what that digital reconstruction has and has not achieved. Peer-reviewed literature published between January 2015 and 4 July 2026 was identified through open scholarly indexes, supplemented by citation searching and authoritative institutional documents, and appraised for methodological adequacy, replication, and alignment between evidence and claim. Five findings emerge. First, digital sensing has substantially reduced the marginal cost of estimating SOC concentration, but the accuracy gains reported in cross-sectional calibration studies do not transfer reliably to the detection of change at field scale. Second, the dominant sources of uncertainty in stock change have shifted away from laboratory analysis towards bulk density, sampling depth, spatial variability and soil mass correction, which remain comparatively under-digitised. Third, model-based crediting achieves scalability by importing structural assumptions that empirical resampling would test, and the evidence that ensembles or Bayesian calibration resolve this dependence remains preliminary. Fourth, permanence is not primarily a data problem: saturation behaviour, mineral association and reversibility constrain what any verification architecture can guarantee, and current accounting instruments handle this unevenly. Fifth, protocol heterogeneity produces materially non-equivalent credits from identical management. Confidence is strongest for the descriptive mapping of SOC concentration and weakest for verified, permanent, additional removals at project scale. Priorities include instrumented reference networks, transparent uncertainty propagation, and evaluation of digital tools under smallholder conditions.

Biochar Applications in Climate-Smart Agriculture: Soil Remediation, Carbon Sequestration and Crop Yield Impacts

Anjana Sagar — Tue, 29 Sep 2026 00:00:00 +0000

Biochar is widely proposed as a climate-smart soil amendment because it can immobilise contaminants, retain carbon and improve crop performance. The breadth of these claims can obscure the strong context dependence of individual outcomes and the trade-offs among remediation, carbon accounting and agronomy. This critical narrative review integrates evidence from field studies, mechanistic research, meta-analyses and life-cycle assessments, with literature searched through 4 July 2026. The evidence is strongest for three conclusions. First, biochar can reduce the bioavailability of many cationic potentially toxic elements and improve selected saline, acidic, coarse-textured or structurally degraded soils, but remediation is usually immobilisation rather than contaminant removal and may fail for anionic contaminants or poorly matched products. Second, biochar reliably increases measured soil carbon and a substantial fraction of well-produced biochar carbon can persist on centennial timescales; nevertheless, durable net carbon removal requires feedstock counterfactuals, production and transport emissions, non-carbon-dioxide greenhouse gases, native-soil-carbon responses and safeguards against double counting. Third, crop-yield responses are positive on average but highly heterogeneous, with larger benefits in acidic, low-fertility, low-organic-carbon and coarse-textured soils and much smaller mean effects in many fertile temperate systems. Water- and nitrogen-use efficiencies can improve, although the mechanisms and economic value depend on soil constraints, application rate and co-management. The synthesis supports a constraint-based deployment model: diagnose the soil problem, match biochar properties to that problem, test realistic rates under field conditions, integrate nutrient management, and monitor the claimed environmental outcome over time. Biochar can contribute meaningfully to climate-smart agriculture when treated as a specified material within a whole management system, but generic claims of simultaneous remediation, carbon sequestration and yield enhancement are not scientifically defensible.

Organic Farming Practices and Soil Health: A Critical Appraisal of Evidence, Mechanisms and System Boundaries

Tue, 29 Sep 2026 00:00:00 +0000

Soil health has become a central justification for organic farming, yet the strength of that justification varies considerably across soil functions, spatial scales and accounting conventions. This critical narrative review examines what the accessible evidence supports about the effects of certified organic and closely related low-external-input management on soil chemical, biological and physical condition, and where the literature remains inconsistent or methodologically constrained. Literature was identified through open scholarly indexes and citation tracking, with the final search conducted on 2 July 2026, and appraised for design adequacy, system-boundary treatment, sampling protocol and analytical transparency rather than aggregated quantitatively. The evidence is strongest and most internally consistent for soil biological indicators: microbial biomass, enzyme activity, mycorrhizal colonisation and earthworm populations are repeatedly higher under organic management across climates and crop types, and community composition shifts in ways that plausibly support nutrient mineralisation and disease suppression. Soil organic carbon differences are consistently positive but considerably more fragile, because the largest reported gains depend on imported organic matter whose production carries an off-site carbon cost, and because effect sizes contract sharply when analyses are restricted to systems without net external inputs. Physical benefits are real but selective, appearing chiefly in aggregate stability, infiltration and plant-available water, while compaction indicators respond weakly and are strongly confounded by tillage intensity. Three problems limit confidence across the field: the treatment of organic farming as a single undifferentiated intervention rather than a bundle of separable practices; the inconsistent handling of sampling depth, bulk density and system boundaries; and a marked geographical concentration of evidence in temperate Europe and North America. The soil health advantages of organic management are best interpreted as practice-specific and context-dependent rather than as intrinsic properties of certification, and the practices that generate them are transferable to non-certified systems.

Monitoring of Climate Characteristics During the Summer Season in Iraq

Saad M. Potrous — Tue, 29 Sep 2026 00:00:00 +0000

Climatic characteristics and air-quality conditions were monitored during summer 2026 in Duhok, Baghdad and Basra, representing northern, central and southern Iraq. Weekly observations were recorded from 5 June to 28 August at midday (1:00–2:00 p.m.). The air-pollution values used in this study were treated as pollutant-specific Air Quality Index (AQI) sub-index values for nitrogen dioxide (NO₂), ground-level ozone (O₃), PM10, PM2.5, carbon monoxide (CO) and sulfur dioxide (SO₂), together with atmospheric pressure, wind speed, humidity and UV Index. Weekly data were summarised using means, standard deviations, ranges and 95% confidence intervals; between-governorate differences were evaluated with a Friedman test using week as the blocking factor, monotonic temporal trends with Kendall's tau-b, and associations between particulate-matter indices and climatic variables with Spearman's rho. The highest NO₂ value was 52 in Basra, the highest O₃ value was 65 in Duhok, PM10 reached 182 in Basra and PM2.5 reached 206 in Basra. CO remained at 1 in all three governorates, while the highest SO₂ value was 14 in Baghdad. Friedman tests indicated between-governorate differences for NO₂, O₃, PM10, PM2.5, SO₂, atmospheric pressure, humidity and UV Index (p<0.05), whereas wind speed did not reach statistical significance (p=0.052); CO could not be tested because it showed no variability. UV Index values ranged from 8 to 12. Overall, the findings show spatial and temporal variation in the recorded summer indicators, while the exploratory statistical analyses do not establish causal relationships.