KR20210017919A - Upward longwave radiation calculation method - Google Patents

Abstract

Disclosed is an earth surface upward longwave radiation (ULR) calculation method. The earth surface upward longwave radiation calculation method comprises the steps of: determining outgoing longwave radiation (OLR) in upper atmosphere and atmospheric transmittance in a longwave region by simulating a vertical profile including vertical pressure, vertical temperature, vertical water vapor and vertical ozone according to a radiative transfer model; deriving a regression coefficient for calculating ULR at an earth surface using the determined ULR in the upper atmosphere and atmospheric transmittance in the longwave region; and calculating the ULR from the earth surface by using the ULR in the upper atmosphere and the earth surface temperature based on the derived regression coefficient.

Description

Calculation method of the upward longwave radiation of the ground surface {UPWARD LONGWAVE RADIATION CALCULATION METHOD}

The present invention relates to a method of calculating the upward long-wave radiation of the ground surface, and more particularly, to a method of calculating the upward long-wave radiation of the ground surface by using the upward long-wave radiation from the surface temperature and the upper atmosphere.

Upward Longwave Radiation (ULR) is one of the components of the Earth's surface radiation balance and is the amount of radiation emitted from the surface to the atmosphere and space. This amount of radiation is an important radiative factor in meteorological prediction, hydrology, and ecology, including net long-wave radiation and pure short-wave radiation for the balance of radiation balance. In addition, since it is an energy essential for energy exchange between the surface and the atmosphere, it can be used for detecting weather and climate change because it shows a change in the amount of radiation depending on the characteristics of the climate and the surface. In particular, it is essential for energy circulation in high latitudes and polar regions.

Long-wave radiation above the surface can be observed from the earth radiometer, which is a ground-based observation equipment, but the observed data can only represent the area, and in the case of oceans, mountains, and polar regions, it is difficult to observe radiation amount and manage equipment due to poor observation environment. There is this. Therefore, to solve this problem, algorithms are being developed to calculate the up-to-surface long-wave radiation based on satellite data.

Conventionally, in order to calculate such an upward longwave radiation of the surface, the surface temperature, the surface emission rate, and the downward longwave radiation (DLR) are used as input data as shown in Equation 1 below.

<Equation 1>

는 지표면 방출률,

는 슈테판-볼츠만 (Stefan-Boltzmann) 상수 (

),

는 지표면 온도이다.here

Is the surface emission rate,

Is the Stefan-Boltzmann constant (

),

Is the surface temperature.

However, the surface emission rate, which is the data input in Equation 1 above, is limitedly calculated using satellite data because it is virtually impossible to observe the ground-based surface as in the case of the upward longwave radiation to the surface. In other words, since the surface must be observed from an artificial satellite, the surface emission rate is not calculated for areas where clouds exist.

Therefore, as long as there is an area where clouds exist, real-time calculation of the surface emission rate for all areas is impossible. In order to solve this problem, a method of producing as daily or monthly average data by collecting the results calculated under cloudless conditions for all observation areas for a long period of time is also used, but in the case of the surface emission rate, the value varies with time. In this case, a large error of 10% or more may occur every hour. Therefore, the data on the surface emission rate is an essential factor in the calculation of the upward long-wave radiation to the surface, but there is a problem with great uncertainty.

The present invention relates to a method of calculating the upward long-wave radiation of the ground surface, and more specifically, provides a method of calculating the upward long-wave radiation of the ground by using the upward long-wave radiation at the surface temperature and the upper atmosphere.

In an embodiment of the present invention, a method for calculating the upward longwave radiation at the top of the atmosphere is performed by simulating a vertical profile including vertical air pressure, vertical temperature, vertical water vapor amount, and vertical ozone amount according to a radiation transmission model. , OLR) and determining the atmospheric transmittance of the long wave region; Deriving a regression coefficient for calculating Upward Longwave Radiation (ULR) at the ground surface by using the determined upward longwave radiation at the top of the atmosphere and the atmospheric transmittance of the long wave region; And calculating the upward long-wave radiation from the ground surface by using the upward long-wave radiation from the upper atmosphere and the surface temperature on the basis of the derived regression coefficient.

The present invention relates to a method of calculating the upward long-wave radiation on the ground surface, and more specifically, it is possible to calculate the upward long-wave radiation on the ground surface by using the upward long-wave radiation at the surface temperature and the upper atmosphere without using the surface emission rate with high uncertainty.

1 is a flow chart showing a flow of an algorithm for calculating an upward longwave radiation to a ground surface according to an embodiment of the present invention.
FIG. 2 is a view showing atmospheric transmittance in a long-wave region according to a surface temperature and an upward long-wave radiation scattering diagram at an upper end of the atmosphere according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a comparison of CERES's up-to-ground long-wave radiation and the up-to-ground long-wave radiation calculated through the present invention according to an embodiment of the present invention.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. However, since various changes may be made to the embodiments, the scope of the rights of the patent application is not limited or limited by these embodiments. It should be understood that all changes, equivalents, or substitutes to the embodiments are included in the scope of the rights.

The terms used in the examples are used for illustrative purposes only and should not be interpreted as limiting. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance.

In addition, in the description with reference to the accompanying drawings, the same reference numerals are assigned to the same components regardless of the reference numerals, and redundant descriptions thereof will be omitted. In describing the embodiments, when it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the embodiments, the detailed description thereof will be omitted.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flow chart showing a flow of an algorithm for calculating an upward longwave radiation to a ground surface according to an embodiment of the present invention.

Weather variables such as surface temperature have very similar observations, weather models, and satellite results, and the uncertainty is very low compared to other weather variables. In addition, since the calculation error of the long-wave radiation down to the ground surface is also small, and the emission rate of the ground surface usually has a value between 0.9 and 1, the second term on the right in Equation 1 above has a relatively very small value.

In the present invention, in order to solve the problem of calculating the upward long-wave radiation of the ground surface, an algorithm for calculating the upward long-wave radiation of the ground surface is provided that does not use the ground surface emission rate. Such an algorithm for calculating the upward long-wave radiation of the ground surface can calculate the upward long-wave radiation of the ground using the atmospheric transmittance, and the atmospheric transmittance can be defined as in Equation 2 below.

<Equation 2>

는 장파 영역의 대기투과도를 의미하고, OLR(Outgoing Longwave Radiation)은 대기 상단에서의 상향장파복사를 나타낸다. 그러면, 본 발명은 식 2로부터 식 3과 같은 지표면 상향장파복사를 도출할 수 있다.here,

Denotes the atmospheric transmittance in the long-wave region, and OLR (Outgoing Longwave Radiation) denotes the upward long-wave radiation at the top of the atmosphere. Then, the present invention can derive the upward long-wave radiation from Equation 2 as shown in Equation 3.

<Equation 3>

Here, the atmospheric transmittance showed a relationship as shown in FIG. 2 with the upward long-wave radiation at the top of the atmosphere. At this time, the algorithm for calculating the upward long-wave radiation to the surface of the present invention simulates the upward long-wave radiation and atmospheric transmittance at the top of the atmosphere according to the following weather conditions using a radiation transfer model, SBDART (Santa Barbara DISORT Atmospheric Radiative Transfer). SBDART simulation is a standard atmosphere, including tropical, mid-latitude summer and winter, subarctic summer and winter, US standard total 6 types, solar zenith angle (18 types) with 5° intervals from 0° to 85°, and 7 optical thickness of clouds (2 , 4, 8, 16, 32, 64, 128), and 9 types of cloud altitude (0, 2, 4, 6, 8, 10, 12, 14, 16), and the surface temperature, absorbed gas and trace gas were standard. The default of the atmosphere was used.

As shown in FIG. 2, the upward long-wave radiation at the top of the atmosphere, which is a simulated result according to the ground surface temperature set as a default in the standard atmosphere, showed a linear relationship with the atmospheric transmittance. Therefore, from the linear relationship between the two variables, Equation 3 above can be expressed as Equation 4 below.

<Equation 4>

는 지표면 상향장파복사 산출을 위한 회귀계수로 아래의 표 1과 같다.here

Is the regression coefficient for calculating the long-wave radiation above the surface, and is shown in Table 1 below.

That is, the algorithm for calculating the upward longwave radiation of the surface of the present invention does not use the surface emission rate with high uncertainty to calculate the upward longwave radiation of the surface, but the upward longwave radiation at the top of the atmosphere based on a regression coefficient for calculating the upward longwave radiation of the surface. And it is possible to provide a method of calculating the upward long-wave radiation of the surface by using only the surface temperature.

)을 포함하는 연직 프로파일을 복사 전달 모델에 따라 시뮬레이션 함으로써 단계(120)에서와 같이 대기 상단에서의 상향장파복사 및 장파 영역의 대기투과도를 결정할 수 있다. In other words, the algorithm for calculating the upward long-wave radiation of the ground surface of the present invention is in step 110 as shown in FIG.

) By simulating the vertical profile including) according to the radiation transmission model, as in step 120, it is possible to determine the upward long-wave radiation at the top of the atmosphere and the atmospheric transmittance of the long-wave region.

Subsequently, in step 130, the algorithm for calculating the upward longwave radiation of the ground surface of the present invention can derive a regression coefficient for calculating the upward longwave radiation from the surface by using the determined upward longwave radiation at the top of the atmosphere and the atmospheric transmittance of the long wave region. In step 140, the upward long-wave radiation at the top of the atmosphere and the surface temperature may be used to calculate the upward long-wave radiation at the ground surface based on the derived regression coefficient.

FIG. 3 is a diagram illustrating a comparison of CERES's up-to-ground long-wave radiation and the up-to-ground long-wave radiation calculated through the present invention according to an embodiment of the present invention.

In order to test the calculation accuracy of the algorithm for calculating the upward longwave radiation developed through the present invention, a comparative analysis was performed with the upward longwave radiation of the Terra CERES (Clouds and the Earth's Radiant Energy System) SYN1d (synoptic 1 degree). This data provides data on the daily average surface upward longwave radiation gridded at 1° x 1° over the global domain. The earth surface upward longwave radiation calculated through the algorithm for calculating the upward longwave radiation of the surface of the present invention is based on the surface temperature of the Local Data Assimilation and Prediction System (LDAPS) and the upward longwave radiation data from the upper atmosphere of the Himawari-8 Advanced Himawari Imager (AHI). It was used as input data, and the results calculated from January 1st to December 31st, 2016 were averaged daily in a 1° ⅹ 1° grid for the Korean Peninsula.

)와 본 발명의 지표면 상향장파복사 산출 알고리즘을 통해 산출된 지표면 상향장파복사(

)는 유사한 복사량 분포를 보였고, 이 둘의 차이는 도 3의 c) 및 d)와 같이 지역적으로 최대 20

(평균 1.69

) 그리고 10% (평균 0.44%) 미만의 차이를 보였다. 이때 평균적인 편이(bias)와 표준제곱근오차(Root Mean Square Error, RMSE) 그리고 상관계수는 1.69

와 6.39

그리고 0.98로 나타났다. 즉, CERES의 지표면 상향장파복사 평균인 380.74

를 기준으로 백분율 bias (%bias=bias/meanⅹ100%)와 백분율 RMSE (%RMSE=RMSE/meanⅹ100%)는 0.44%와 1.69%의 작은 차이이다.As a result, as shown in Fig. 3, the upward long-wave radiation of the ground surface calculated through CERES (

) And the surface upward longwave radiation calculated through the algorithm of the present invention

) Showed a similar distribution of radiation, and the difference between the two was up to 20 locally as shown in Fig. 3 c) and d).

(Average 1.69

) And less than 10% (average 0.44%). At this time, the average bias, the root mean square error (RMSE) and the correlation coefficient are 1.69

And 6.39

And it turned out to be 0.98. In other words, the average of CERES's upward long-wave radiation on the surface of the earth is 380.74

The percentage bias (%bias=bias/mean×100%) and the percentage RMSE (%RMSE=RMSE/mean×100%) are small differences between 0.44% and 1.69%.

Therefore, it is possible to calculate the amount of radiation with high accuracy without the use of a surface emission rate that has a difficult calculation condition and a large uncertainty for the calculation of the upward long wave radiation calculated through the algorithm for calculating the upward long wave radiation to the surface of the present invention. This can be widely used in hydrology that requires real-time monitoring and meteorological and climate studies that require a surface energy balance.

Meanwhile, the method for calculating the upward long-wave radiation on the ground surface according to the present invention is written as a program that can be executed in a computer, and can be implemented in various recording media such as magnetic storage media, optical reading media, and digital storage media.

Implementations of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or combinations thereof. Implementations may include a data processing device, e.g., a programmable processor, a computer, or a computer program product, e.g., a machine-readable storage device (computer-readable It can be implemented as a computer program tangibly embodied in a possible medium). Computer programs, such as the computer program(s) described above, may be recorded in any type of programming language including compiled or interpreted languages, and as a standalone program or in a module, component, subroutine, or computing environment. It can be deployed in any form, including as other units suitable for the use of. A computer program can be deployed to be processed on one computer or multiple computers at one site, or to be distributed across multiple sites and interconnected by a communication network.

Processors suitable for processing a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. In general, the processor will receive instructions and data from read-only memory or random access memory or both. Elements of the computer may include at least one processor that executes instructions and one or more memory devices that store instructions and data. In general, a computer may include one or more mass storage devices, such as magnetic, magnetic-optical disks, or optical disks, to store data, receive data from, transmit data to, or both It may be combined so as to be. Information carriers suitable for embodying computer program instructions and data are, for example, semiconductor memory devices, for example, magnetic media such as hard disks, floppy disks and magnetic tapes, Compact Disk Read Only Memory (CD-ROM). ), Optical Media such as DVD (Digital Video Disk), Magnetic-Optical Media such as Floptical Disk, ROM (Read Only Memory), RAM (RAM) , Random Access Memory), flash memory, EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), and the like. The processor and memory may be supplemented by or included in a special purpose logic circuit structure.

Further, the computer-readable medium may be any available medium that can be accessed by a computer, and may include all computer storage media.

While this specification includes details of a number of specific implementations, these should not be construed as limiting to the scope of any invention or claim, but rather as a description of features that may be peculiar to a particular embodiment of a particular invention. It must be understood. Certain features described herein in the context of separate embodiments may be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment can also be implemented in multiple embodiments individually or in any suitable sub-combination. Furthermore, although features operate in a particular combination and may be initially described as so claimed, one or more features from a claimed combination may in some cases be excluded from the combination, and the claimed combination may be a subcombination. Or sub-combination variations.

Likewise, although operations are depicted in the drawings in a specific order, it should not be understood that such operations must be performed in that particular order or sequential order shown, or that all illustrated operations must be performed in order to obtain a desired result. In certain cases, multitasking and parallel processing can be advantageous. In addition, separation of the various device components in the above-described embodiments should not be understood as requiring such separation in all embodiments, and the program components and devices described are generally integrated together into a single software product or packaged in multiple software products. You should understand that you can.

On the other hand, the embodiments of the present invention disclosed in the specification and drawings are merely presented specific examples to aid understanding and are not intended to limit the scope of the present invention. It is obvious to those of ordinary skill in the art that other modifications based on the technical idea of the present invention may be implemented in addition to the embodiments disclosed herein.

Claims (1)

Determining outgoing longwave radiation (OLR) at the top of the atmosphere and atmospheric transmittance in a long wave region by simulating a vertical profile including vertical air pressure, vertical temperature, vertical water vapor amount, and vertical ozone amount according to a radiation transmission model;
Deriving a regression coefficient for calculating Upward Longwave Radiation (ULR) at the ground surface by using the determined upward longwave radiation at the top of the atmosphere and the atmospheric transmittance of the long wave region; And
Calculating the upward long-wave radiation from the ground surface by using the upward long-wave radiation at the upper end of the atmosphere and the surface temperature based on the derived regression coefficient
A method of calculating the upward longwave radiation of the ground surface comprising a.

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