Google Earth Engine ——数据全解析专辑（COPERNICUS/S5P/OFFL/L3_HCHO）大气甲醛 (HCHO) 浓度的离线高分辨率数据集

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发布于 2024-02-02 11:20:15

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发布于 2024-02-02 11:20:15

OFFL/L3_HCHO

This dataset provides offline high-resolution imagery of atmospheric formaldehyde (HCHO) concentrations.

Formaldehyde is an intermediate gas in almost all oxidation chains of non-methane volatile organic compounds (NMVOC), leading eventually to CO2. Non-Methane Volatile Organic Compounds (NMVOCs) are, together with NOx, CO and CH4, among the most important precursors of tropospheric O3. The major HCHO source in the remote atmosphere is CH4 oxidation. Over the continents, the oxidation of higher NMVOCs emitted from vegetation, fires, traffic and industrial sources results in important and localized enhancements of the HCHO levels. The seasonal and inter-annual variations of the formaldehyde distribution are principally related to temperature changes and fire events, but also to changes in anthropogenic activities. HCHO concentrations in the boundary layer can be directly related to the release of short-lived hydrocarbons, which mostly cannot be observed directly from space. [More information]

OFFL/L3_HCHO
该数据集提供了大气甲醛 (HCHO) 浓度的离线高分辨率图像。

甲醛是几乎所有非甲烷挥发性有机化合物 (NMVOC) 氧化链中的中间气体，最终会导致 CO2。非甲烷挥发性有机化合物 (NMVOC) 与 NOx、CO 和 CH4 一起，是对流层 O3 最重要的前体。偏远大气中的主要 HCHO 来源是 CH4 氧化。在各大洲，植被、火灾、交通和工业源排放的较高 NMVOC 的氧化导致 HCHO 水平的重要和局部提高。甲醛分布的季节性和年际变化主要与温度变化和火灾事件有关，但也与人为活动的变化有关。边界层中的 HCHO 浓度可能与短寿命碳氢化合物的释放直接相关，而这些碳氢化合物大多无法直接从太空中观察到。 [更多信息]

Dataset Availability

2018-12-05T12:14:36 - 2021-09-04T00:00:00

Dataset Provider

European Union/ESA/Copernicus

Collection Snippet

ee.ImageCollection("COPERNICUS/S5P/OFFL/L3_HCHO")

Resolution

0.01 degrees

Bands Table

Name	Description	Min*	Max*	Units
tropospheric_HCHO_column_number_density	Tropospheric HCHO column number density.	-0.0172	0.0074	mol/m^2
tropospheric_HCHO_column_number_density_amf	Tropospheric air mass factor.	0.177	4.058	mol/m^2
HCHO_slant_column_number_density	HCHO slant column number density.	-0.01425	0.00735	mol/m^2
cloud_fraction	Effective cloud fraction. See the [Sentinel 5P L2 Input/Output Data Definition Spec](https://sentinels.copernicus.eu/documents/247904/3119978/Sentinel-5P-Level-2-Input-Output-Data-Definition), p.220.	0	1	fraction
sensor_azimuth_angle	Azimuth angle of the satellite at the ground pixel location (WGS84); angle measured East-of-North.	-180	180	degrees
sensor_zenith_angle	Zenith angle of the satellite at the ground pixel location (WGS84); angle measured away from the vertical.	0.098	66.57	degrees
solar_azimuth_angle	Azimuth angle of the Sun at the ground pixel location (WGS84); angle measured East-of-North.	-180	180	degrees
solar_zenith_angle	Zenith angle of the satellite at the ground pixel location (WGS84); angle measured away from the vertical.	8.76	101.17	degrees

* = Values are estimated

Name	Type	Description
ALGORITHM_VERSION	String	The algorithm version used in L2 processing. It's separate from the processor (framework) version, to accommodate different release schedules for different products.
BUILD_DATE	String	The date, expressed as milliseconds since 1 Jan 1970, when the software used to perform L2 processing was built.
HARP_VERSION	Int	The version of the HARP tool used to grid the L2 data into an L3 product.
INSTITUTION	String	The institution where data processing from L1 to L2 was performed.
L3_PROCESSING_TIME	Int	The date, expressed as milliseconds since 1 Jan 1970, when Google processed the L2 data into L3 using harpconvert.
LAT_MAX	Double	The maximum latitude of the asset (degrees).
LAT_MIN	Double	The minimum latitude of the asset (degrees).
LON_MAX	Double	The maximum longitude of the asset (degrees).
LON_MIN	Double	The minimum longitude of the asset (degrees).
ORBIT	Int	The orbit number of the satellite when the data was acquired.
PLATFORM	String	Name of the platform which acquired the data.
PROCESSING_STATUS	String	The processing status of the product on a global level, mainly based on the availability of auxiliary input data. Possible values are "Nominal" and "Degraded".
PROCESSOR_VERSION	String	The version of the software used for L2 processing, as a string of the form "major.minor.patch".
PRODUCT_ID	String	Id of the L2 product used to generate this asset.
PRODUCT_QUALITY	String	Indicator that specifies whether the product quality is degraded or not. Allowed values are "Degraded" and "Nominal".
SENSOR	String	Name of the sensor which acquired the data.
SPATIAL_RESOLUTION	String	Spatial resolution at nadir. For most products this is `3.5x7km2`, except for `L2__O3__PR`, which uses `28x21km2`, and `L2__CO____` and `L2__CH4___`, which both use `7x7km2`. This attribute originates from the CCI standard.
TIME_REFERENCE_DAYS_SINCE_1950	Int	Days from 1 Jan 1950 to when the data was acquired.
TIME_REFERENCE_JULIAN_DAY	Double	The Julian day number when the data was acquired.
TRACKING_ID	String	UUID for the L2 product file.

CLOSEIMPORT

代码：

var collection = ee.ImageCollection('COPERNICUS/S5P/NRTI/L3_HCHO')
  .select('tropospheric_HCHO_column_number_density')
  .filterDate('2019-06-01', '2019-06-06');

var band_viz = {
  min: 0.0,
  max: 0.0003,
  palette: ['black', 'blue', 'purple', 'cyan', 'green', 'yellow', 'red']
};

Map.addLayer(collection.mean(), band_viz, 'S5P HCHO');
Map.setCenter(0.0, 0.0, 2);

影像：