An Interpretation of Cloud Overlap Statistics

Abstract Observational studies have shown that the vertical overlap of cloudy layers separated by clear sky can exceed that of the random overlap assumption, suggesting a tendency toward minimum overlap. In addition, the rate of decorrelation of vertically continuous clouds with increasing layer separation is sensitive to the horizontal scale of the cloud scenes used. The authors give a heuristic argument that these phenomena result from data truncation, where overcast or single cloud layers are removed from the analysis. This occurs more frequently as the cloud sampling scale falls progressively below the typical cloud system scale. The postulate is supported by sampling artificial cyclic and subsequently more realistic fractal cloud scenes at various length scales. The fractal clouds indicate that the degree of minimal overlap diagnosed in previous studies for discontinuous clouds could result from sampling randomly overlapped clouds at spatial scales that are 30%–80% of the cloud system scale. Removing scenes with cloud cover exceeding 50% from the analysis reduces the impact of data truncation, with discontinuous clouds not minimally overlapped and the decorrelation of continuous clouds less sensitive to the sampling scale. Using CloudSat–CALIPSO data, a decorrelation length scale of approximately 4.0 km is found. In light of these results, the previously documented dependence of overlap decorrelation length scale on latitude is not entirely a physical phenomenon but can be reinterpreted as resulting from sampling cloud systems that increase significantly in size from the tropics to midlatitudes using a fixed sampling scale.

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On what scales can GOSAT flux inversions constrain anomalies in terrestrial ecosystems?

10.5194/acp-2018-909 ◽

2019 ◽

Author(s):

Brendan Byrne ◽

Dylan B. A. Jones ◽

Kimberly Strong ◽

Saroja M. Polavarapu ◽

Anna B. Harper ◽

...

Keyword(s):

Spatial Scales ◽

Net Ecosystem Exchange ◽

Terrestrial Ecosystems ◽

Atmospheric Co2 ◽

Strong Correlations ◽

Climate Anomalies ◽

Temperature And Precipitation ◽

The Tropics ◽

Emergent Constraint ◽

The Impact

Abstract. Interannual variations in temperature and precipitation impact the carbon balance of terrestrial ecosystems, leaving an imprint in atmospheric CO2. Quantifying the impact of climate anomalies on the net ecosystem exchange (NEE) of terrestrial ecosystems can provide a constraint to evaluate terrestrial biosphere models against, and may provide an emergent constraint on the response of terrestrial ecosystems to climate change. We investigate the spatial scales over which interannual variability in NEE can be constrained using atmospheric CO2 observations from the Greenhouse Gases Observing Satellite (GOSAT). NEE anomalies are calculated by performing a series of inversion analyses using the GEOS-Chem model to assimilate GOSAT observations. Monthly NEE anomalies are compared to proxies, variables which are associated with anomalies in the terrestrial carbon cycle, and to upscaled NEE estimates from FLUXCOM. Strong agreement is found in the timing of anomalies in the GOSAT flux inversions with soil temperature and FLUXCOM. Strong correlations are obtained (P RNINO3.4) in the tropics on continental and larger scales, and in the northern extratropics on sub-continental scales during the summer (R2 ≥ 0.49). These results, in addition to a series of observing system simulation experiments that were conducted, provide evidence that GOSAT flux inversions can isolate anomalies in NEE on continental and larger scales. However, in both the tropics and northern extratropics, the agreement between the inversions and the proxies/FLUXCOM is sensitive to the flux inversion configuration. Our results suggest that regional scales are likely the minimum scales that can be resolved in the tropics using GOSAT observations, but obtaining robust NEE anomaly estimates on these scales may be difficult.

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Impact of SSM/I Observations Related to Moisture, Clouds, and Precipitation on Global NWP Forecast Skill

Monthly Weather Review ◽

10.1175/2007mwr2292.1 ◽

2008 ◽

Vol 136 (7) ◽

pp. 2713-2726 ◽

Cited By ~ 30

Author(s):

G. A. Kelly ◽

P. Bauer ◽

A. J. Geer ◽

P. Lopez ◽

J-N. Thépaut

Keyword(s):

Initial Conditions ◽

Forecast Skill ◽

Clear Sky ◽

Microwave Imager ◽

Set Up ◽

The Tropics ◽

The Impact ◽

Northern And Southern Hemispheres ◽

Experiment Duration

Abstract This paper presents the results from the Observing System Experiments (OSEs) with the current ECMWF data assimilation and modeling system for quantifying the impact on both analysis and forecast quality of Special Sensor Microwave Imager (SSM/I) observations sensitive to moisture and clouds as well as precipitation. SSM/I radiances have been assimilated operationally in clear-sky areas for 8 yr and in cloud- and rain-affected areas since June 2005. This paper examines experiments set up such that clear-sky and rain-affected observations were either added to a baseline with a restricted observing system configuration or withdrawn from the full system. The experiment duration was 10 weeks of which the first 14 days were excluded from the evaluation to allow the system to lose the memory of the initial conditions at day −1. It is shown that both clear-sky and rain-affected observations account for the bulk correction of moisture in the ECMWF analysis. SSM/I data adds 1 day of forecast skill over the first 48 h when evaluated in addition to a baseline-observing system. In the tropics, the rain-affected data contributes more skill to the moisture forecast than the clear-sky data at 700 hPa and above. In the Northern and Southern Hemispheres, the effect is generally weaker and slightly in favor of clear-sky observations. A similar performance can be seen with respect to the wind vector forecast skill, which reflects the connection between the analysis of moisture and dynamics.

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All-sky assimilation of infrared radiances sensitive to mid- and upper-tropospheric moisture and cloud

Atmospheric Measurement Techniques ◽

10.5194/amt-12-4903-2019 ◽

2019 ◽

Vol 12 (9) ◽

pp. 4903-4929 ◽

Cited By ~ 4

Author(s):

Alan J. Geer ◽

Stefano Migliorini ◽

Marco Matricardi

Keyword(s):

Weather Forecasting ◽

Deep Convection ◽

Cloud Detection ◽

Clear Sky ◽

Atmospheric Sounding ◽

Beneficial Impact ◽

Infrared Radiances ◽

The Tropics ◽

The Impact ◽

Better Than

Abstract. All-sky assimilation of infrared (IR) radiances has not yet become operational at any weather forecasting centre, but it promises to bring new observations in sensitive areas and avoid the need for cloud detection. A new all-sky IR configuration gives results comparable to (and in some areas better than) clear-sky assimilation of the same data, meaning that operational implementation is now feasible. The impact of seven upper-tropospheric water vapour (WV) sounding channels from the Infrared Atmospheric Sounding Interferometer (IASI) is evaluated in both all-sky and clear-sky approaches. All-sky radiative transfer simulations (and the forecast model's cloud fields) are now sufficiently accurate that systematic errors are comparable to those of clear-sky assimilation outside of a few difficult areas such as deep convection. All-sky assimilation brings 65 % more data than clear-sky assimilation globally, with the biggest increases in midlatitude storm tracks and tropical convective areas. However, all-sky gives slightly less weight to any one observation than in the clear-sky approach. In the midlatitudes, all-sky and clear-sky assimilation have similarly beneficial impact on mid- and upper-tropospheric dynamical forecast fields. Here the addition of data in cloudy areas is offset by the slightly lower weight given to the observations. But in the tropics, all-sky assimilation is significantly more beneficial than clear-sky assimilation, with improved dynamical short-range forecasts throughout the troposphere and stratosphere.

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The impact of cirrus clouds on tropical troposphere-to-stratosphere transport

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-6-1725-2006 ◽

2006 ◽

Vol 6 (2) ◽

pp. 1725-1747 ◽

Cited By ~ 4

Author(s):

T. Corti ◽

B. P. Luo ◽

Q. Fu ◽

H. Vömel ◽

T. Peter

Keyword(s):

Deep Convection ◽

Cirrus Clouds ◽

Cirrus Cloud ◽

Clear Sky ◽

Second Stage ◽

Third Stage ◽

Tropical Troposphere ◽

The Tropics ◽

The Impact

Abstract. Although it is well known that air enters the stratosphere preferentially through upwelling in the tropics, the exact mechanisms of troposphere-to-stratosphere transport (TST) are still unknown. Previously proposed mechanisms have been found either to be too slow (e.g., clear sky upwelling) to provide agreement with in situ tracer measurements, or to be insufficient in mass flux to act as a major supply for the Brewer-Dobson circulation (e.g., convective overshooting). In this study we evaluate whether the lofting of air via cirrus cloud-radiation interaction might offer an alternative path for TST, which is responsible for a significant fraction of the observed air mass transport. We find that a combination of deep convection and subsequent upwelling associated with cirrus clouds and clear sky can explain the supply of air for the Brewer-Dobson circulation. Thus, upwelling associated with cirrus clouds offers a mechanism for the missing second stage, which links the first stage of TST, deep convection, to the third stage, the Brewer-Dobson circulation.

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All-sky assimilation of infrared radiances sensitive to mid- and upper-tropospheric moisture and cloud

10.5194/amt-2019-9 ◽

2019 ◽

Cited By ~ 2

Author(s):

Alan J. Geer ◽

Stefano Migliorini ◽

Marco Matricardi

Keyword(s):

Weather Forecasting ◽

Deep Convection ◽

Cloud Detection ◽

Clear Sky ◽

Atmospheric Sounding ◽

Beneficial Impact ◽

Infrared Radiances ◽

The Tropics ◽

The Impact ◽

Better Than

Abstract. All-sky assimilation of infrared (IR) radiances has not yet become operational at any weather forecasting centre but it promises to bring new observations in sensitive areas and it avoids the need for cloud detection. A new all-sky IR configuration gives results comparable to (and in some areas better than) clear-sky assimilation of the same data, meaning that operational implementation is now feasible. The impact of 7 upper-tropospheric water vapour (WV) sounding channels from the Infrared Atmospheric Sounding Interferometer (IASI) is evaluated in both all-sky and clear-sky approaches. All-sky radiative transfer simulations (and the forecast model’s cloud fields) are now sufficiently accurate that systematic errors are comparable to those of clear-sky assimilation outside of a few difficult areas such as deep-convection. All-sky assimilation brings 65 % more data than clear-sky assimilation globally, with the biggest increases in midlatitude storm tracks and tropical convective areas. However all-sky gives slightly less weight to any one observation than in the clear-sky approach. In the midlatitudes, all-sky and clear-sky assimilation have similarly beneficial impact on mid- and upper-tropospheric dynamical forecast fields. Here the addition of data in cloudy areas is offset by the slightly lower weight given to the observations. But in the tropics, all-sky assimilation is significantly more beneficial than clear-sky assimilation, with improved dynamical short-range forecasts throughout the troposphere and stratosphere.

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The impact of cirrus clouds on tropical troposphere-to-stratosphere transport

Atmospheric Chemistry and Physics ◽

10.5194/acp-6-2539-2006 ◽

2006 ◽

Vol 6 (9) ◽

pp. 2539-2547 ◽

Cited By ~ 104

Author(s):

T. Corti ◽

B. P. Luo ◽

Q. Fu ◽

H. Vömel ◽

T. Peter

Keyword(s):

Deep Convection ◽

Cirrus Clouds ◽

Cirrus Cloud ◽

Clear Sky ◽

Second Stage ◽

Third Stage ◽

Tropical Troposphere ◽

The Tropics ◽

The Impact

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On what scales can GOSAT flux inversions constrain anomalies in terrestrial ecosystems?

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-13017-2019 ◽

2019 ◽

Vol 19 (20) ◽

pp. 13017-13035 ◽

Cited By ~ 5

Author(s):

Brendan Byrne ◽

Dylan B. A. Jones ◽

Kimberly Strong ◽

Saroja M. Polavarapu ◽

Anna B. Harper ◽

...

Keyword(s):

Interannual Variability ◽

Spatial Scales ◽

Net Ecosystem Exchange ◽

Terrestrial Ecosystems ◽

Atmospheric Co2 ◽

Terrestrial Biosphere ◽

Climate Anomalies ◽

Temperature And Precipitation ◽

The Tropics ◽

The Impact

Abstract. Interannual variations in temperature and precipitation impact the carbon balance of terrestrial ecosystems, leaving an imprint in atmospheric CO2. Quantifying the impact of climate anomalies on the net ecosystem exchange (NEE) of terrestrial ecosystems can provide a constraint to evaluate terrestrial biosphere models against and may provide an emergent constraint on the response of terrestrial ecosystems to climate change. We investigate the spatial scales over which interannual variability in NEE can be constrained using atmospheric CO2 observations from the Greenhouse Gases Observing Satellite (GOSAT). NEE anomalies are calculated by performing a series of inversion analyses using the GEOS-Chem adjoint model to assimilate GOSAT observations. Monthly NEE anomalies are compared to “proxies”, variables that are associated with anomalies in the terrestrial carbon cycle, and to upscaled NEE estimates from FLUXCOM. Statistically significant correlations (P<0.05) are obtained between posterior NEE anomalies and anomalies in soil temperature and FLUXCOM NEE on continental and larger scales in the tropics, as well as in the northern extratropics on subcontinental scales during the summer (R2≥0.49), suggesting that GOSAT measurements provide a constraint on NEE interannual variability (IAV) on these spatial scales. Furthermore, we show that GOSAT flux inversions are generally better correlated with the environmental proxies and FLUXCOM NEE than NEE anomalies produced by a set of terrestrial biosphere models (TBMs), suggesting that GOSAT flux inversions could be used to evaluate TBM NEE fluxes.

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Genetic structure in the endosymbiont Breviolum ‘muscatinei’ is correlated with geographical location, environment and host species

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2020.2896 ◽

2021 ◽

Vol 288 (1946) ◽

pp. 20202896

Author(s):

Brendan H. Cornwell ◽

Luis Hernández

Keyword(s):

Genetic Structure ◽

Host Species ◽

Isolation By Distance ◽

Spatial Scales ◽

Geographical Location ◽

Wide Range ◽

Genetic Patterns ◽

Coral Reef Ecosystems ◽

The Tropics ◽

The Impact

Corals and cnidarians form symbioses with dinoflagellates across a wide range of habitats from the tropics to temperate zones. Notably, these partnerships create the foundation of coral reef ecosystems and are at risk of breaking down due to climate change. This symbiosis couples the fitness of the partners, where adaptations in one species can benefit the holobiont. However, the scales over which each partner can match their current—and future—environment are largely unknown. We investigated population genetic patterns of temperate anemones ( Anthopleura spp.) and their endosymbiont Breviolum ‘muscatinei’ , across an extensive geographical range to identify the spatial scales over which local adaptation is possible. Similar to previously published results, two solitary host species exhibited isolation by distance across hundreds of kilometres. However, symbionts exhibited genetic structure across multiple spatial scales, from geographical location to depth in the intertidal zone, and host species, suggesting that symbiont populations are more likely than their hosts to adaptively mitigate the impact of increasing temperatures.

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Scale dependence of galaxy biasing investigated by weak gravitational lensing: An assessment using semi-analytic galaxies and simulated lensing data

Astronomy and Astrophysics ◽

10.1051/0004-6361/201732248 ◽

2018 ◽

Vol 613 ◽

pp. A15 ◽

Cited By ~ 13

Author(s):

Patrick Simon ◽

Stefan Hilbert

Keyword(s):

Gravitational Lensing ◽

Spatial Scales ◽

Scale Dependence ◽

Reconstruction Technique ◽

Weak Gravitational Lensing ◽

Physical Scale ◽

The Galaxy ◽

Galaxy Bias ◽

The Impact ◽

Lens Galaxies

Galaxies are biased tracers of the matter density on cosmological scales. For future tests of galaxy models, we refine and assess a method to measure galaxy biasing as a function of physical scalekwith weak gravitational lensing. This method enables us to reconstruct the galaxy bias factorb(k) as well as the galaxy-matter correlationr(k) on spatial scales between 0.01hMpc−1≲k≲ 10hMpc−1for redshift-binned lens galaxies below redshiftz≲ 0.6. In the refinement, we account for an intrinsic alignment of source ellipticities, and we correct for the magnification bias of the lens galaxies, relevant for the galaxy-galaxy lensing signal, to improve the accuracy of the reconstructedr(k). For simulated data, the reconstructions achieve an accuracy of 3–7% (68% confidence level) over the abovek-range for a survey area and a typical depth of contemporary ground-based surveys. Realistically the accuracy is, however, probably reduced to about 10–15%, mainly by systematic uncertainties in the assumed intrinsic source alignment, the fiducial cosmology, and the redshift distributions of lens and source galaxies (in that order). Furthermore, our reconstruction technique employs physical templates forb(k) andr(k) that elucidate the impact of central galaxies and the halo-occupation statistics of satellite galaxies on the scale-dependence of galaxy bias, which we discuss in the paper. In a first demonstration, we apply this method to previous measurements in the Garching-Bonn Deep Survey and give a physical interpretation of the lens population.

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The Impact of RDP Measures on the Diversification of Agriculture and Rural Development—Seeking Additional Livelihoods: The Case of Poland

Agriculture ◽

10.3390/agriculture11030253 ◽

2021 ◽

Vol 11 (3) ◽

pp. 253

Author(s):

Mirosław Biczkowski ◽

Aleksandra Jezierska-Thöle ◽

Roman Rudnicki

Keyword(s):

Rural Development ◽

Rural Areas ◽

Spatial Scales ◽

Development Program ◽

Spatial Diversity ◽

Agricultural Activities ◽

Synthetic Index ◽

Two Measures ◽

The Impact ◽

The Eu

The paper’s main aim is to assess the measures implemented within the Rural Development Program (RDP) 2007–2013 in Poland. This programme is dedicated to the diversification of business activities in rural areas and rural livelihood and, thus, the improvement of the multifunctionality of rural areas. The analysis covered two measures from Axis 3, Improvement of the quality of life in rural areas and diversification of rural economy: M311, diversification into non-agricultural activities; and M312, Establishment and development of micro-enterprise. The study and the discussion are presented from a geographical perspective and, in a broader context, take into account several conditions (natural, urban, agricultural and historical) and the spatial diversity of the allocation of European Union (EU) funds. Models of a policy of multifunctional rural development, implemented after accession to the EU, are presented. The research’s spatial scope covers Poland’s territory on two spatial scales: the system of regions (16 NUTS2 units) and poviats (314 LAU level 1 units). The analysis covers all the projects implemented in Poland under the two measures of Axis 3 of the RDP 2007–2013. A set of conditions was prepared for all LAU1 units, forming the background for assessing the impact of the EU funds on the development of non-agricultural activities. To determine the relationship between the RDP measures and the selected groups of conditions, a synthetic index and a correlation index are used. They are also used to determine the mutual relations between the two analyzed activities in terms of the spatial scales used. Access to the EU funds (RDP) has considerably enlarged the opportunities for accelerating agricultural modernisation and restructuration towards multifunctional development, as well as the opportunities for implementing new development and work methods in the countryside in Poland. The attractiveness of the two studied RDP measures varied across regions. The beneficiaries’ activity depended on the local potential (resources), culture and tradition of the region, and size and potential of the farm. In the areas where agriculture is deeply rooted, beneficiaries were more willing to engage in ventures tapping into the resources available in their farms. Thus, they create additional livelihood of income and workplaces for household members. In turn, the beneficiaries from the areas where farms are smaller and economically weaker often undertake activities related to setting up a new business (outside farming).

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