Cloud Properties and Their Seasonal and Diurnal Variability from TOVS Path-B

2006 ◽  
Vol 19 (21) ◽  
pp. 5531-5553 ◽  
Author(s):  
C. J. Stubenrauch ◽  
A. Chédin ◽  
G. Rädel ◽  
N. A. Scott ◽  
S. Serrar
Keyword(s):  
South America ◽  
Diurnal Cycle ◽  
Cloud Amount ◽  
Early Morning ◽  
Infrared Observation ◽  
Relevant Variable ◽  
Diurnal Variability ◽  
Cloud Properties ◽  
Early Afternoon ◽  
The Tropics

Abstract Eight years of cloud properties retrieved from Television Infrared Observation Satellite-N (TIROS-N) Observational Vertical Sounder (TOVS) observations aboard the NOAA polar orbiting satellites are presented. The relatively high spectral resolution of these instruments in the infrared allows especially reliable cirrus identification day and night. This dataset therefore provides complementary information to the International Satellite Cloud Climatology Project (ISCCP). According to this dataset, cirrus clouds cover about 27% of the earth and 45% of the Tropics, whereas ISCCP reports 19% and 25%, respectively. Both global datasets agree within 5% on the amount of single-layer low clouds, at 30%. From 1987 to 1995, global cloud amounts remained stable to within 2%. The seasonal cycle of cloud amount is in general stronger than its diurnal cycle and it is stronger than the one of effective cloud amount, the latter the relevant variable for radiative transfer. Maximum effective low cloud amount over ocean occurs in winter in SH subtropics in the early morning hours and in NH midlatitudes without diurnal cycle. Over land in winter the maximum is in the early afternoon, accompanied in the midlatitudes by thin cirrus. Over tropical land and in the other regions in summer, the maximum of mesoscale high opaque clouds occurs in the evening. Cirrus also increases during the afternoon and persists during night and early morning. The maximum of thin cirrus is in the early afternoon, then decreases slowly while cirrus and high opaque clouds increase. TOVS extends information of ISCCP during night, indicating that high cloudiness, increasing during the afternoon, persists longer during night in the Tropics and subtropics than in midlatitudes. A comparison of seasonal and diurnal cycle of high cloud amount between South America, Africa, and Indonesia during boreal winter has shown strong similarities between the two land regions, whereas the Indonesian islands show a seasonal and diurnal behavior strongly influenced by the surrounding ocean. Deeper precipitation systems over Africa than over South America do not seem to be directly reflected in the horizontal coverage and mesoscale effective emissivity of high clouds.

scholarly journals Diurnal variation of high-level clouds from the synergy of AIRS and IASI space-borne infrared sounders

2019 ◽  
Author(s):  
Artem G. Feofilov ◽  
Claudia J. Stubenrauch
Keyword(s):  
Diurnal Variation ◽  
Diurnal Cycle ◽  
Cloud Amount ◽  
Convective Cloud ◽  
Cirrus Clouds ◽  
Local Times ◽  
Cloud Type ◽  
Cloud Data ◽  
High Level ◽  
The Tropics

Abstract. Among the processes governing the energy balance of our planet, high-level clouds, due to their coverage of about 30 %, play an important role. The net radiative effect (cooling or warming of the planet) of these clouds strongly depends on their emissivity. The combination of cloud data retrieved from two space-borne infrared sounders, the Atmospheric InfraRed Sounder, AIRS, and the Infrared Atmospheric Sounding Interferometer, IASI, which observe the Earth at four local times per day, allows to investigate the diurnal variation of these high-level clouds, distinguishing between high opaque, cirrus, and thin cirrus clouds. We demonstrate that the diurnal phase and amplitude of high-level clouds can be estimated from these measurements with an uncertainty of 1.5 h and 20 %, respectively. We have applied the developed methodology to AIRS and IASI observations and obtained monthly distributions of diurnal phase and amplitude for the period 0f 2008–2015. In agreement with other studies, the diurnal cycle is the largest over land in the tropics. At higher latitudes, the diurnal cycle is the largest during the summer. For the regions of high diurnal activity over land, the diurnal amplitudes of cloud amount are about 7 % for high opaque clouds, 9 % for cirrus, and 7 % for thin cirrus clouds. Over ocean, these values are 2 to 3 times smaller. The diurnal cycle of tropical thin cirrus seems to be similar over land and over ocean, with a minimum in the morning (9 h LT) and a maximum during night (1 h LT). Tropical high opaque clouds have a maximum in the evening (21 h LT over land), a few hours after the peak of convective rain. This lag is explained by the fact that this cloud type not only includes the convective cores, but also part of the thicker anvils. Tropical cirrus (with an emissivity > 0.5 or visible optical depth > 1.4) show a maximum amount during night (1 h LT over land). This lag indicates that they may be a part of the deep convective cloud systems. However, the peak local times also vary regionally. We are providing a global monthly database of detected diurnal cycle amplitude and phase for each cloud type.

scholarly journals The effects of timing and rate of marine cloud brightening aerosol injection on albedo changes during the diurnal cycle of marine stratocumulus clouds

2013 ◽  
Vol 13 (3) ◽  
pp. 1659-1673 ◽  
Author(s):  
A. K. L. Jenkins ◽  
P. M. Forster ◽  
L. S. Jackson
Keyword(s):  
Point Source ◽  
Diurnal Cycle ◽  
Radiative Forcing ◽  
Early Morning ◽  
Injection Time ◽  
Liquid Water Path ◽  
Marine Stratocumulus ◽  
Cloud Albedo ◽  
Aerosol Effect ◽  
Early Afternoon

Abstract. The marine-cloud brightening geoengineering technique has been suggested as a possible means of counteracting the positive radiative forcing associated with anthropogenic atmospheric CO2 increases. The focus of this study is to quantify the albedo response to aerosols injected into marine stratocumulus cloud from a point source at different times of day. We use a cloud-resolving model to investigate both weakly precipitating and non-precipitating regimes. Injection into both regimes induces a first indirect aerosol effect. Additionally, the weakly precipitating regime shows evidence of liquid water path gain associated with a second indirect aerosol effect that contributes to a more negative radiative forcing, and cloud changes indicative of a regime change to more persistent cloud. This results in a cloud albedo increase up to six times larger than in the non-precipitating case. These indirect effects show considerable variation with injection at different times in the diurnal cycle. For the weakly precipitating case, aerosol injection results in domain average increases in cloud albedo of 0.28 and 0.17 in the early and mid morning (03:00:00 local time (LT) and 08:00:00 LT respectively) and 0.01 in the evening (18:00:00 LT). No cloud develops when injecting into the cloud-free early afternoon (13:00:00 LT). However, the all-sky albedo increases (which include both the indirect and direct aerosol effects) are highest for early morning injection (0.11). Mid-morning and daytime injections produce increases of 0.06, with the direct aerosol effect compensating for the lack of cloud albedo perturbation during the cloud-free early afternoon. Evening injection results in an increase of 0.04. For the weakly precipitating case considered, the optimal injection time for planetary albedo response is the early morning. Here, the cloud has more opportunity develop into a more persistent non-precipitating regime prior to the dissipative effects of solar heating. The effectiveness of the sea-spray injection method is highly sensitive to diurnal injection time and the direct aerosol effect of an intense aerosol point source. Studies which ignore these factors could overstate the effectiveness of the marine cloud brightening technique.

Prediction of the Diurnal Change Using a Multimodel Superensemble. Part I: Precipitation

2007 ◽  
Vol 135 (10) ◽  
pp. 3613-3632 ◽  
Author(s):  
T. N. Krishnamurti ◽  
C. Gnanaseelan ◽  
A. Chakraborty
Keyword(s):  
Cloud Model ◽  
Early Morning ◽  
Diurnal Change ◽  
Individual Member ◽  
Forecast Errors ◽  
The Tibetan Plateau ◽  
Large Variability ◽  
Diurnal Variability ◽  
Geographical Regions ◽  
The Tropics

Abstract Modeling the geographical distribution of the phase and amplitude of the diurnal change is a challenging problem. This paper addresses the issues of modeling the diurnal mode of precipitation over the Tropics. Largely an early morning precipitation maximum over the oceans and an afternoon rainfall maximum over land areas describe the first-order diurnal variability. However, large variability in phase and amplitude prevails even within the land and oceanic areas. This paper addresses the importance of a multimodel superensemble for much improved prediction of the diurnal mode as compared to what is possible from individual models. To begin this exercise, the skills of the member models, the ensemble mean of the member models, a unified cloud model, and the superensemble for the prediction of total rain as well as its day versus night distribution were examined. Here it is shown that the distributions of total rain over the earth (tropical belt) and over certain geographical regions are predicted reasonably well (RMSE less than 18%) from the construction of a multimodel superensemble. This dataset is well suited for addressing the diurnal change. The large errors in phase of the diurnal modes in individual models usually stem from numerous physical processes such as the cloud radiation, shallow and deep cumulus convection, and the physics of the planetary boundary layer. The multimodel superensemble is designed to reduce such systematic errors and provide meaningful forecasts. That application for the diurnal mode appears very promising. This paper examines some of the regions such as the Tibetan Plateau, the eastern foothills of the Himalayas, and the Amazon region of South America that are traditionally difficult for modeling the diurnal change. In nearly all of these regions, errors in phase and amplitude of the diurnal mode of precipitation increase with the increased length of forecasts. Model forecast errors on the order of 6–12 h for phase and 50% for the amplitude are often seen from the member models. The multimodel superensemble reduces these errors and provides a close match (RMSE < 6 h) to the observed phase. The percent of daily rain and their phases obtained from the multimodel superensemble at 3-hourly intervals for different regions of the Tropics showed a closer match (pattern correlation about 0.4) with the satellite estimates. This is another area where the individual member models conveyed a much lower skill.

scholarly journals Model-based Climatology of Diurnal Variability in Stratospheric Ozone as a Data Analysis Tool

2019 ◽  
Author(s):  
Stacey M. Frith ◽  
Pawan K. Bhartia ◽  
Luke D. Oman ◽  
Natalya A. Kramarova ◽  
Richard D. McPeters ◽  
...  
Keyword(s):  
Diurnal Cycle ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Analysis Tool ◽  
Diurnal Variability ◽  
Data Merging ◽  
Wide Range ◽  
Synchronous Orbit ◽  
Mean Differences ◽  
The Tropics

Abstract. Observational studies of stratospheric ozone often involve data from multiple instruments that measure the ozone at different times of day. There has been an increased awareness of the potential impact of the diurnal cycle when interpreting measurements of stratospheric ozone at altitudes in the mid to upper stratosphere. To address this issue we present a climatological representation of diurnal variations in ozone with a half hour temporal resolution as a function of latitude, pressure and month, based on output from the NASA GEOS-GMI chemistry model run. This climatology can be applied in a wide range of ozone data analyses, including data inter-comparisons, data merging, and analysis of data from a single platform in a non-sun-synchronous orbit. We evaluate the diurnal climatology by comparing mean differences between ozone measurements made at different local solar times to the differences predicted by the diurnal model. The ozone diurnal cycle is a complicated function of latitude, pressure and season, with variations of less than 5 % in the tropics and sub-tropics, increasing to more than 15 % near the polar summer boundary in the upper stratosphere. These results compare well with previous modeling simulations and are supported by similar size variations in satellite observations. We present several example applications of the climatology in currently relevant data studies. We also compare this diurnal climatology to the diurnal signal from a previous iteration of the free-running GEOS Chemistry Climate Model (GEOSCCM) and to the ensemble runs of GEOS-GMI to test the sensitivity of the model diurnal cycle to changes in model formulation and simulated time period.

Evaluation of the Daylight Cycle of Model-Predicted Cloud Amount and Condensed Water Path over Europe with Observations from MSG SEVIRI

2009 ◽  
Vol 22 (7) ◽  
pp. 1749-1766 ◽  
Author(s):  
R. A. Roebeling ◽  
E. van Meijgaard
Keyword(s):  
Diurnal Cycle ◽  
Climate Models ◽  
Climate Model ◽  
Cloud Amount ◽  
Daily Maximum ◽  
Accurate Information ◽  
Water Path ◽  
Cloud Properties ◽  
Condensed Water ◽  
The Mediterranean

Abstract The evaluation of the diurnal cycle of cloud amount (CA) and cloud condensed water path (CWP) as predicted by climate models receives relatively little attention, mostly because of the lack of observational data capturing the diurnal cycle of such quantities. The Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard the geostationary Meteosat-8 satellite is the first instrument able to provide accurate information on diurnal cycles during daylight hours of cloud properties over land and ocean surfaces. This paper evaluates the daylight cycle of CA and CWP as predicted by the Regional Atmospheric Climate Model version 2 (RACMO2), using corresponding SEVIRI retrievals. The study is done for Europe using hourly cloud properties retrievals from SEVIRI during the summer months from May to September 2004. The results of this study show that SEVIRI-retrieved daylight cycles of CA and CWP provide a powerful tool for identifying climate model deficiencies. Over Europe the SEVIRI retrievals of cloud condensed water paths comprise about 80% liquid water and about 20% ice water. The daylight cycles of CA and CWP from SEVIRI show large spatial variations in their mean values and time of daily maximum and daytime-normalized amplitude. In general, RACMO2 overestimates CWP by about 30% and underestimates CA by about 20% as compared to SEVIRI. The largest amplitudes are observed in the Mediterranean and northern Africa. For the greater part of the ocean and coastal areas the time of daily maximum CWP is found during morning, whereas over land this maximum is found after local solar noon. These features are reasonably well captured by RACMO2. In the Mediterranean and continental Europe RACMO2 tends to predict maximum CWP associated with convection to occur about two hours earlier than SEVIRI indicates.

scholarly journals Trends in Global Cloud Cover in Two Decades of HIRS Observations

2005 ◽  
Vol 18 (15) ◽  
pp. 3021-3031 ◽  
Author(s):  
Donald Wylie ◽  
Darren L. Jackson ◽  
W. Paul Menzel ◽  
John J. Bates
Keyword(s):  
Cloud Cover ◽  
Cloud Amount ◽  
Cloud Detection ◽  
Total Cloud Cover ◽  
Infrared Observation ◽  
Upper Troposphere ◽  
Polar Orbiting Satellite ◽  
The Tropics ◽  
High Clouds ◽  
Infrared Radiometer

Abstract The frequency of cloud detection and the frequency with which these clouds are found in the upper troposphere have been extracted from NOAA High Resolution Infrared Radiometer Sounder (HIRS) polar-orbiting satellite data from 1979 to 2001. The HIRS/2 sensor was flown on nine satellites from the Television Infrared Observation Satellite-Next Generation (TIROS-N) through NOAA-14, forming a 22-yr record. Carbon dioxide slicing was used to infer cloud amount and height. Trends in cloud cover and high-cloud frequency were found to be small in these data. High clouds show a small but statistically significant increase in the Tropics and the Northern Hemisphere. The HIRS analysis contrasts with the International Satellite Cloud Climatology Project (ISCCP), which shows a decrease in both total cloud cover and high clouds during most of this period.

scholarly journals Evaluating the Diurnal Cycle of Upper-Tropospheric Ice Clouds in Climate Models Using SMILES Observations

2015 ◽  
Vol 72 (3) ◽  
pp. 1022-1044 ◽  
Author(s):  
Jonathan H. Jiang ◽  
Hui Su ◽  
Chengxing Zhai ◽  
T. Janice Shen ◽  
Tongwen Wu ◽  
...  
Keyword(s):  
Diurnal Cycle ◽  
Climate Models ◽  
Space Station ◽  
Temporal Patterns ◽  
Spatial And Temporal Patterns ◽  
Ice Clouds ◽  
Diurnal Variability ◽  
Diurnal Cycles ◽  
Ice Cloud ◽  
The Tropics

Abstract Upper-tropospheric ice cloud measurements from the Superconducting Submillimeter Limb Emission Sounder (SMILES) on the International Space Station (ISS) are used to study the diurnal cycle of upper-tropospheric ice cloud in the tropics and midlatitudes (40°S–40°N) and to quantitatively evaluate ice cloud diurnal variability simulated by 10 climate models. Over land, the SMILES-observed diurnal cycle has a maximum around 1800 local solar time (LST), while the model-simulated diurnal cycles have phases differing from the observed cycle by −4 to 12 h. Over ocean, the observations show much smaller diurnal cycle amplitudes than over land with a peak at 1200 LST, while the modeled diurnal cycle phases are widely distributed throughout the 24-h period. Most models show smaller diurnal cycle amplitudes over ocean than over land, which is in agreement with the observations. However, there is a large spread of modeled diurnal cycle amplitudes ranging from 20% to more than 300% of the observed over both land and ocean. Empirical orthogonal function (EOF) analysis on the observed and model-simulated variations of ice clouds finds that the first EOF modes over land from both observation and model simulations explain more than 70% of the ice cloud diurnal variations and they have similar spatial and temporal patterns. Over ocean, the first EOF from observation explains 26.4% of the variance, while the first EOF from most models explains more than 70%. The modeled spatial and temporal patterns of the leading EOFs over ocean show large differences from observations, indicating that the physical mechanisms governing the diurnal cycle of oceanic ice clouds are more complicated and not well simulated by the current climate models.

scholarly journals Diurnal variation of high-level clouds from the synergy of AIRS and IASI space-borne infrared sounders

2019 ◽  
Vol 19 (22) ◽  
pp. 13957-13972 ◽  
Author(s):  
Artem G. Feofilov ◽  
Claudia J. Stubenrauch
Keyword(s):  
Diurnal Variation ◽  
Diurnal Cycle ◽  
Cloud Amount ◽  
Convective Cloud ◽  
Local Times ◽  
Cloud Data ◽  
The Earth ◽  
Cooling Effects ◽  
High Level ◽  
The Tropics

Abstract. By covering about 30 % of the Earth and by exerting a strong greenhouse effect, high-level clouds play an important role in the energy balance of our planet. Their warming and cooling effects within the atmosphere strongly depend on their emissivity. The combination of cloud data from two space-borne infrared sounders, the Atmospheric InfraRed Sounder, AIRS, and the Infrared Atmospheric Sounding Interferometer, IASI, which observe the Earth four times per day, allows us to investigate the diurnal variation of these high-level clouds by distinguishing between high opaque, cirrus, and thin cirrus clouds. We demonstrate that the diurnal phase and amplitude of high-level clouds can be estimated from these measurements with an uncertainty of 1.5 h and 20 %, respectively. By applying the developed methodology to AIRS and IASI cloud observations for the period of 2008–2015, we obtained monthly geographical distributions of diurnal phase and amplitude at a spatial resolution of 1∘ latitude ×1∘ longitude. In agreement with other studies, the diurnal cycle of high-level clouds is the largest over land in the tropics. At higher latitudes, their diurnal cycle is the largest during the summer. For selected continental regions we found diurnal amplitudes of cloud amount of about 7 % for high opaque clouds and for thin cirrus, and 9 % for cirrus. Over ocean, these values are 2 to 3 times smaller. The diurnal cycle of tropical thin cirrus seems to be similar over land and over ocean, with a minimum in the morning (09:00 LT) and a maximum during the night (01:00 LT). Tropical high opaque clouds have a maximum in the evening (21:00 LT over land), a few hours after the peak of convective rain. This lag can be explained by the fact that this cloud type includes not only the convective cores, but also part of the thicker anvils. Tropical cirrus show maximum coverage during the night (01:00 LT over land). This lag indicates that they are part of the deep convective cloud systems. However, the peak local times also vary regionally. We are providing a global monthly database of detected diurnal cycle amplitude and phase for each of these three high-level cloud types.

Diurnal Variations in Rainfall and Precipitation Asymmetry of Tropical Cyclones in the Northwest Pacific Region

2021 ◽  
pp. 1-52
Author(s):  
Xinyan Zhang ◽  
Weixin Xu
Keyword(s):  
Diurnal Cycle ◽  
Radial Distance ◽  
Vertical Wind Shear ◽  
Early Morning ◽  
Diurnal Variations ◽  
Precipitation Intensity ◽  
Northwest Pacific ◽  
Diurnal Changes ◽  
Precipitation Frequency ◽  
Diurnal Variability

AbstractThis study investigates diurnal variations of tropical cyclone precipitation in the northwest Pacific (NWP) region, including the South China Sea (SCS) and adjacent landmasses. Diurnal cycles of TC rainfall show significant land-sea contrasts. The primary peak of (unconditional) mean TC rain rate occurs in the early morning (06 LT) and the afternoon (15 LT) over the ocean and land, respectively. Both the total and heavy TC precipitation extend further inland in the afternoon, while nocturnal heavy TC rain is more confined to the coast. A significant semidiurnal cycle of TC precipitation is observed over the ocean, i.e., a secondary peak near 18 LT. The diurnal cycle of TC rainfall also depends on precipitation frequency, intensity, and radial distance from the TC center. Over the ocean, though TC precipitation intensity shows a pronounced diurnal cycle, its precipitation frequency exhibits virtually no diurnal variation. Over land, TC precipitation frequency markedly peaks in the afternoon (15 LT), while its precipitation intensity interestingly maximizes in the early morning (03-06 LT). Diurnal variations of TC asymmetric rainfall structure are consistent with diurnal changes of vertical wind shear. Over the SCS, maximum precipitation located in the downshear-left quadrant and is the most extensive in the morning. However, this heavy rain area shrinks and shifts downshear-ward in the afternoon, consistent with changes of the magnitude (reduced) and direction (clockwise) of shear. In contrast, TCs over the open ocean of NWP (OWP) have little diurnal variability of precipitation asymmetry, due mainly to a diurnally invariant shear environment.

scholarly journals Role of Diurnal Warm Layers in the Diurnal Cycle of Convection over the Tropical Indian Ocean during MISMO

2010 ◽  
Vol 138 (6) ◽  
pp. 2426-2433 ◽  
Author(s):  
H. Bellenger ◽  
Y. N. Takayabu ◽  
T. Ushiyama ◽  
K. Yoneyama
Keyword(s):  
Indian Ocean ◽  
Diurnal Cycle ◽  
Tropical Indian Ocean ◽  
Early Morning ◽  
Heat Fluxes ◽  
Surface Heat Fluxes ◽  
Boundary Layer Processes ◽  
Early Afternoon

Abstract The role of air–sea interaction in the diurnal variations of convective activity during the suppressed and developing stages of an intraseasonal convective event is analyzed using in situ observations from the Mirai Indian Ocean cruise for the Study of the Madden–Julian oscillation (MJO)-convection Onset (MISMO) experiment. For the whole period, convection shows a clear average diurnal cycle with a primary maximum in the early morning and a secondary one in the afternoon. Episodes of large diurnal sea surface temperature (SST) variations are observed because of diurnal warm layer (DWL) formation. When no DWL is observed, convection exhibits a diurnal cycle characterized by a maximum in the early morning, whereas when DWL forms, convection increases around noon and peaks in the afternoon. Boundary layer processes are found to control the diurnal evolution of convection. In particular, when DWL forms, the change in surface heat fluxes can explain the decrease of convective inhibition and the intensification of the convection during the early afternoon.

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