Related Experiment Video
Updated: Jun 12, 2025
13:27
Exploring the Effects of Atmospheric Forcings on Evaporation: Experimental Integration of the Atmospheric Boundary Layer and Shallow Subsurface
Published on: June 8, 2015
8.7K
Observation-constrained projections reveal longer-than-expected dry spells
Irina Y Petrova1, Diego G Miralles2, Florent Brient3
1H-CEL, Ghent University, Ghent, Belgium. irina.petrova@ugent.be.
Nature
|September 18, 2024
Summary
Climate models underestimate future drought severity. A new method using emergent constraints (EC) reveals longer annual dry spells, indicating greater drought risks globally than previously projected.
Area of Science:
- Climate science
- Environmental modeling
- Drought prediction
Background:
- Climate models project worsening dry extremes globally.
- Current projections lack confidence in magnitude and timing, leaving societies unprepared for increased drought events.
Purpose of the Study:
- To reduce uncertainty in climate model projections of drought.
- To improve predictions of the longest annual dry spell (LAD) using an emergent constraint (EC).
Main Methods:
- Constraining climate model projections with observational data.
- Utilizing a newly proposed emergent constraint (EC) to refine LAD predictions.
- Analyzing two generations of climate models to identify biases and feedback mechanisms.
Main Results:
- The EC method reduced uncertainty in LAD predictions by 10-26% globally.
- EC-corrected projections show a 42-44% greater increase in LAD compared to current scenarios.
- Global mean land-only LAD may increase by 10 days by the end of the century.
Conclusions:
- Societies and ecosystems face higher and earlier drought risks than anticipated.
- Emergent constraints offer a pathway to more reliable drought projections.
- Understanding model biases is crucial for accurate climate change impact assessments.
Related Concept Videos
01:17Precipitation and Co-precipitation
1.7K
Precipitation and coprecipitation methods can be used to separate a mixture of ions in a solution. In qualitative inorganic analysis, ions that form sparingly soluble precipitates with the same reagent are separated based on the differences in solubility products. For example, consider the separation of Cu(II) and Fe(II) ions by precipitation as insoluble sulfides. First, copper(II) sulfide is precipitated by the addition of acidic H2S, where the dissociation of H2S is suppressed. Adding H2S...
1.7K
01:12Precipitation Processes
431
The experimental conditions in a gravimetric analysis should be optimized to maximize the particle size and purity of the obtained precipitate. Ideally, the concentration of the precipitating reagent should be low with effective stirring to maintain low relative supersaturation for the growth of large crystals. In homogeneous precipitation, the precipitant is slowly generated by a chemical reaction in the solution to avoid local reagent excesses. For example, urea decomposes gradually to...
431
01:03Precipitation Gravimetry
5.5K
Precipitation gravimetry is based on converting an analyte into a sparingly soluble precipitate, which is separated by filtration and weighed. An ideal precipitate should be pure, insoluble, of known composition, and easily filtered from the reaction mixture.
In determining nickel by gravimetric analysis, a precipitant of ethanolic dimethylglyoxime is added to a hot nickel salt solution. This is quickly followed by the dropwise addition of dilute ammonia solution until precipitation occurs. A...
In determining nickel by gravimetric analysis, a precipitant of ethanolic dimethylglyoxime is added to a hot nickel salt solution. This is quickly followed by the dropwise addition of dilute ammonia solution until precipitation occurs. A...
5.5K
01:10Types of Coprecipitation
579
Coprecipitation is the contamination of a precipitate by otherwise soluble species and occurs via different processes. In colloidal precipitates, coprecipitation occurs via surface adsorption. For instance, barium sulfate has a primary layer of adsorbed barium ions and a secondary layer of nitrate counterions. This results in contamination of the precipitate by barium nitrate.
Sometimes, ions in a crystal lattice can undergo isomorphous replacement by inclusions of similar charge and size. For...
Sometimes, ions in a crystal lattice can undergo isomorphous replacement by inclusions of similar charge and size. For...
579
03:12Freezing Point Depression and Boiling Point Elevation
34.5K
Boiling Point Elevation
The boiling point of a liquid is the temperature at which its vapor pressure is equal to ambient atmospheric pressure. Since the vapor pressure of a solution is lowered due to the presence of nonvolatile solutes, it stands to reason that the solution’s boiling point will subsequently be increased. Vapor pressure increases with temperature, and so a solution will require a higher temperature than will pure solvent to achieve any given vapor pressure, including one...
The boiling point of a liquid is the temperature at which its vapor pressure is equal to ambient atmospheric pressure. Since the vapor pressure of a solution is lowered due to the presence of nonvolatile solutes, it stands to reason that the solution’s boiling point will subsequently be increased. Vapor pressure increases with temperature, and so a solution will require a higher temperature than will pure solvent to achieve any given vapor pressure, including one...
34.5K
01:18Boundary Layer Characteristics
58
When a fluid encounters a solid surface, a boundary layer forms due to the interaction between the fluid's motion and the stationary surface. This phenomenon is characterized by a thin region adjacent to the surface where viscous forces dominate, influencing the fluid's velocity profile. The development of the boundary layer begins at the leading edge of the surface and evolves as the fluid moves downstream.As the fluid flows over the surface, friction between the fluid and the wall slows down...
58